How's this?
I think the simplest way to both ensure it's as popular as ANH and make it plausible that he would think of it is to combine elements of TPM and ANH...
Which would mean combining elements of the second films in each trilogy and then combine elements of the third films in each trilogy to follow... but all of that is later...
First things first...
Synopsis of The Star Wars: Episode I, released 1977.
The Jedi are a powerful Wizard-Samurai/private security force which is used by the Galactic Republic to enforce their rule and provide assistance in complicated negotiation agreements with the citizens of said Republic. The trouble is that the Republic is rife with corruption and mired in bureaucratic in-fighting and the Jedi have their hands full...
(The following two paragraphs may or may not be explained in such detail... at least at first...)
The lush and peaceful world of Utapau has been blockaded by the Trade Confederation which is a large and ever more powerful trading alliance that has enough resources to buy favor with Senators in the Galactic Republic. What makes this more alarming is its recent merger with an enormous Outer Rim confederation of pirates and mercenaries who have been raiding Republic shipments at will without consequence and with alarming speed and efficiency. The Trade Confederation now has an even larger fleet at its disposal, an enormous army, more resources than ever, representation in the Galactic Senate, and it is also now influenced by a mysterious investor and former commander of the newly assimilated pirate hordes. Few have seen him and none can describe the figure known as Sidious, but he is known to be as powerful as he is brutal. The Jedi fear that the shroud of darkness over this figure and the underground dealings of the seemingly invincible Trade Confederation are a sign of the return of an evil force, eradicated ages ago, known as the Sith.
The Trade Confederation is blockading the peaceful world of Utapau, at the orders of Sidious to procure its control over Galactic trade routes and the Jedi Knights are sent to negotiate. However, they are tricked and attacked by the TC. Rescuing the defiant Queen Amidala of Utapau the Jedi blast out of the capitol city of Yavin in her Royal transport. A scroll will set this up in simpler and more engaging terms...
The film opens with the Queen's transport ship carrying Quigonn Jinn (Played by Sir Alec Guiness) and Ben Kenobi (played by? He must be much younger than Guiness, but perhaps slightly older than MacGregor in TPM. He is also already a knight, having previously been Jinn's padawaan) being attacked by a Trade Confederation blockade vessel (similar in look to a Star Destroyer) over the planet of Tatooine as it holds the fugitive Queen Amidala (Carrie Fischer). Some brief explanation provides this background as well as the importance of the Queen making it to the capitol city-world of Alderaan to beg for the Senate's intervention.
The ship is being boarded by Droid Troopers, an army of cheaply built but readily available battle droids built and employed by the Trade Confederation and also sold by the TC to outside bidders - including a modified version which supplements the Army of the Galactic Republic. (Imagine Droid Troopers as a cross between Battle Droids and Stormtroopers and are essentially actors acting as white armored robot warriors in suits.) The skeleton crew is being slaughtered and the Jedi Knights are fighting through the corridors towards the entrance in which the Droid Troopers are entering. The Queen is taken to an escape pod with her personal astromech droid, R2-D2. "Darth Maul" (or something along those lines. I want the character to be same, but the name can be different, or has to be really... He is facially like Maul but the rest of the suit is Vader's? A little more flexible though, he's a martial artist.) enters with his guards and briefly confronts the Jedi who have initiated a self destruct sequence on the ship, knowing that it is docked with the TC ship. The lightsaber fight is brief but intense as the Dark Lord must make his escape from the Royal Transport and disengage it from his Trade Confederation blockade vessel before it explodes...
The Queen and the Jedi narrowly escape the explosion which destroys the Transport and cripples the Trade Confederation ship. With the Trade Confederation distracted with the damage to their own vessel, the escape pods are not attacked and the Queen, Jedi, and R2 land safely on Tatooine... in the middle of nowhere.
They use R2's scanners to read a moisture farming settlement nearby and head in that direction. They are surprise attacked by Sand People and - somehow- before the Jedi can react, the Sand People are counter attacked and then frightened off by a mysterious robed figure who turns out to be a young desert boy. He takes them to his home, the moisture farm they were looking for. This is where they meet Shmi Starkiller and her young (but not as young as Jake Lloyd) son, Anakinn (Mark Hamill acting a few years younger), the farm boy who saved them. We also meet the droid he has built, C-3PO.
Anakinn is also the youngest Pod Racer in history - the only human to be able to do it, supposedly and while his immediate goals are to become a starfighter pilot, he has always dreamed of being a Jedi Knight. The mother and son were slaves of Jabba the Hutt until Anakinn won their freedom in a race. It was the only race he ever won. At dinner, Anakinn asks if the men are Jedi due to their "laser swords" and also pesters his mother about leaving to join the academy to become a Star Fighter Pilot for the Republic. She responds that she needs him there. Quigonn tells Ben privately that this may be the perfect padawaan for Kenobi as it seems the Force is stronger with him than with anyone else in the galaxy. Kenobi is reluctant. It is also murmured that Starkiller was an immaculate conception. The young boy has also begun to fall in love with the Queen who is in disguise as a refugee from Utapau.
Meanwhile, Droid Troopers and Darth Maul are searching the planet for the Jedi and the Queen and they're hot on their trail. Anakinn takes Quigonn to Mos Eisley Spaceport to find a ship to transport them to Alderaan (the capitol planet of the Galaxy and a sprawling urban paradise) to receive full Republic aid for the planet Utapau.
At the lively Cantina, Quigonn meets and hires Han Solo and Chewbacca and books passage on their ship the Millennium Falcon to Alderaan (All of this similar to ANH) but in order to afford the hefty price, Jinn decides they will need to enter Anakinn in the upcoming Pod Race. Anakinn is thrilled but insists that if he wins, as payment, they give part of the prize money to his mother and take him with them in their quest.
After their meeting, Han Solo is confronted by Greedo on behalf of Jabba the Hutt and it ends in Han killing Greedo in the middle of the Cantina. Immediately afterwards, Han meets with Jabba the Hutt, (a furry wormlike creature and crime kingpin) at the hangar of the Millennium Falcon and assures him that he has his money. Ben isn't sure that the boy can win, and the Queen has her doubts as well ("Aren't you a little short to be a Pod Racer?") but ultimately Quigonn convinces them that they have no other choice but to trust the young man. As this happens, Quigonn gradually begins teaching the boy the ways of the force.
Anakinn wins the Pod Race and receives his money just as Maul closes in on the group. The Millennium Falcon blasts its way out of Mos Eisley spaceport and successfully battles TIEs (unmanned Twin Ion Engine Fighter drones which must be near to a command ship to operate. Essentially Tie Fighters with some characteristics of Vulture Droids?) as they travel to Alderaan (which is a hanging garden metropolis done mostly with interior shots and using matte paintings for the exteriors). During the battle with the TIE drones, Anakinn begins to further earn the respect of them all as he takes the controls of one of the turrets, but is warned by Solo not to get, "cocky"...
While on the ship, Quigonn attempts to instruct Anakinn in the ways of the force and the droids play Chewbacca at a holographic board game where Han advises that they let him win, as Wookiees have been known to pull people's arms out of their sockets when they lose. Anakinn receives his first lightsaber.
While on Alderaan, Quigonn attempts to convince the Jedi Council that Anakinn is the Chosen one of the Jedi prophecies and requests that they allow the former slave to be trained by both himself and Ben Kenobi as Ben Kenobi's padawaan under Quigonn's supervision, but they refuse initially, claiming that he is too old and passionate and would turn to the dark side of the force. They do, however, concede that if he proves himself to them then he would be allowed to be tested by the council. He also informs them that he believes the wicked, ancient Sith have returned and the Trade Federation are somehow involved, using their association with Darth Maul as his clue, as Maul fights as a Sith and is clearly tracking the Queen and her Jedi escorts. (Perhaps all of this is off camera to preserve the existence of Yoda.)
Meanwhile, Queen Amidala meets with Senator Palpatine of Utapau and he convinces her to move for a vote of no confidence in the current Chancellor if he will not assist in resolving the conflict. The Queen decides to mount an internal strike on the Trade Confederation from Utapau. During this time, the love story between Anakinn and Amidala continues to grow and while she views him as little more than a young rogue, a farmboy, and a cute kid, she is impressed with him. He gives her a talisman as a sign of his affection and she thanks him for saving their lives, this is when she reveals herself to Anakinn as the Queen of Utapau.
Scenes also exist between the mysterious Sidious and Darth Maul, and between them both and the generals of the Trade Confederation. This provides more background to the other side of the conflict.
Han Solo refuses to continue on with the group as it isn't his war to fight. He takes his reward and he and Chewie travel back to Tattooine to settle their debts. The Queen, droids, Jedi, and Anakinn travel to Utapau and make their plans.
Upon their secret arrival on Utapau it is discovered that an invasion force has taken the Security Forces hostage and the capitol and surrounding areas are occupied by Droid Troopers on the ground. The blockade of Utapau is now spearheaded by a massive space-station with incredibly destructive potential called The Star Destroyer. The Trade Confederation should not be able to afford this technology and it is revealed through Sidious' scenes speaking with Darth Maul and conversations between the Jedi that the TC are in league with and perhaps under the influence of the ancient Sith. Quigonn's suspicions that the Sith have returned and that Maul is one of them are shown to be true when they see the Star Destroyer and by the time they reach Utapau he is convinced that the Trade Confederation is merely a pawn of the Sith and are acting as a military arm of the revived order, with scores of brainwashed pirate captains and TC leaders as Generals and hordes of Droid Troopers and TIEs as infantry and star fleet respectively. An evil Empire.
The Star Destroyer is protected by an energy shield and it must be deactivated from the inside for any attack on it to succeed. Once the Star Destroyer is destroyed, the TIE drones and all the nearby armies of Droid Troopers will be useless. The Queen takes the droids and Anakinn to the palace to free her Royal Security Force and get some fighters into the air to fight the blockade and destroy the Star Destroyer. Meanwhile, the Jedi fly the transport into the tractor beam of the Star Destroyer, narrowly escaping capture, and stealthily sneak throughout the vessel to disengage the shields.
On the ground and disguised as Droid Troopers - using the shells of two that had been destroyed during the invasion - the Queen and Anakinn race to free the Queen's private army, but are discovered. Anakinn uses his new lightsaber to defend the Queen (who is blasting Troopers with the best of them) and they release the Security Forces just as the Star Destroyer begins to move into position to bombard the capitol city of Yavin into glass. At some point en route to free the Security Forces they have to cross from one balcony to the other and Anakinn uses a rope from a Trooper's utility belt to cross the gap, but not before Amidala kisses him for good luck. Anakinn commandeers a Utapau Starfighter (an X-wing with some N-1 characteristics perhaps? Or the other way around?) and R2 serves as co-pilot as he soars up to join the other fighters on their assault of the Star Destroyer.
The Jedi begin the process of disarming the shield which will automatically disengage after an agonizingly slow series of power downs but are met with Darth Maul. The battle throughout the corridors is intense, with the Jedi fighting in a more samurai style and Maul using something more akin to ninjitsu, kung fu (yes, kung fu lightsaber fighting in 1977), and other fast paced martial arts. It is revealed that the red bladed lightsaber he wields is in fact dual bladed and they are struggling to keep up with the silent Sith Lord.
The Security forces attack the Star Destroyer while the battle rages within. Anakinn, having never piloted a starfighter before, crashes into one of the ports and blasts a whole squadron of drones in the process. The lightsaber fight has made its way to his location but he is caught in a battle of his own with a host of troopers and must distractedly watch from a distance.
Quigonn sees Anakinn watching him and Ben battle the Sith Lord and realizes he can do more good for both Ben who is his up-until-recently padawaan, and Anakinn, the possible Chosen One if he becomes one with the Force. He tells Ben to train the boy, as he is the Chosen One and then allows Maul to kill him. His robes fall limp to the ground. Ben and Anakinn both scream and Anakinn rushes to assist Ben. Ben shouts for Anakinn to "Run, Anakinn, Run!" which he reluctantly does while fighting off a new wave of troopers. R2 is working on kickstarting the starfighter and Anakinn struggles to board it and assist the crippled Security Force.
Ben Kenobi is knocked off a ledge and hangs on for dear life before he flies up and cuts Maul in half. He grabs Quigonn's robes as he watches the two halves of Maul fall down the seemingly bottomless pit. Anakinn shouts at him to board the Starfighter's cramped cargo section to flee the Star Destroyer and finish the battle. Anakinn, Kenobi, and R2 exit the port and turn to fight their way to the ship's now undefended power core. Two or three other starfighters fall into formation behind him and provide them with cover. Ben Kenobi begins to instruct Anakinn as if he were his padawaan, telling him to "Use the Force" and "Let go..."
The fighter formation becomes inundated with attacking Tie fighters while the Queen's group on the ground becomes surrounded by Troopers. The Star Destroyer is in position to bombard the city and all surrounding defenses, even as their troopers remain inside the city quelling the rebellion. After the rebellion in the palace is secured the palace itself will become the next target, and after that, the whole of Utapau will be bombarded mercilessly so that the TC can set up their own garrisons on the world. Surrounded and desperate the good guy's situation on all sides looks grim. Suddenly, the Millennium Falcon appears out of nowhere and Han and Chewie provide cover as Anakinn turns off his sensors and destroys the dreaded Star Destroyer.
All the droid troopers and fighters shut off, the TIEs fall from the sky like fireworks as the troopers collapse harmlessly all around the Queen and her forces. C-3PO knocks one over joyfully. When the fighters return to the city of Yavin, the Queen hugs Han, Chewie, and Ben and kisses Anakinn. C-3PO scolds R2-D2 for being so reckless but commends his bravery. Everyone cheers.
Palpatine becomes the new Supreme Chancellor and Anakinn (with a new James Dean-esque hair cut to match Ben's) is confirmed as Ben Kenobi's padawaan apprentice. Ben tells Anakinn that he may be the Chosen One of Prophecy and that with the return of the Sith, he may be more needed than ever. Anakinn looks upon the funeral for Quigonn, where the robes he left behind were burnt with honor, and his shadowy face turns wickedly determined... as bitter and dark as Mark Hamill pretending to be a couple of years younger can possibly look.
In a victory parade in the city of Yavin on the Planet Utapau with Chancellor Palpatine in attendance putting his hand on Anakinn's shoulder with pride, Queen Amidala awards Kenobi, Anakinn, Solo, and Chewbacca with her most prestigious medal and the crowd roars as they face the camera...
End of synopses.
The film is an enormous smash immediately. Perhaps even more so than ANH was IOTL as there is a little more action but the subtext is smarter and more political. The light is much lighter and the dark is much darker. Very Joseph Campbell.
And with such an unresolved ending... it definitely gets picked for a sequel. The trick now is combining the basic plot of Attack of the Clones with plot elements, locations, and the simple badassedness of Empire Strikes Back. I've got some ideas for this, but first...
What do you think? What are some more ideas? And what are the effects of this TL's Star Wars?
KEEP IT GOING! (I'm having a blast...)