I think it's doable. You'd need to completely re-write the plot and dialogue, of course, but it's doable. For one thing, cut out the romantic crap. Yes, it's all well and good that Anakin turned because he loves Padme so damned much, but the ending there was just...ugh. A good way to incorporate both the romance, the broken heart element, and the feelings of betrayal towards Obi Wan would be to make it so that Padme isn't the virtuous women Anakin think she is, and that she really pines after Obi Wan despite the latter not being interested (since he's, ya know, a Jedi and all).
As Anakin slips deeper and deeper into this idea that a dictatorship is some benevolent way to make the trains run on time, Padme starts to realise that their relationship isn't going to work. Have it revealed that Obi Wan knows about it, but out of love for both his former apprentice and his old friend, he's kept his mouth shut. Padme therefore can be seen confiding in Obi Wan about Anakin's inner turmoils, and Obi Wan in turn tries to help Anakin.
Of course, it goes the wrong way, because Anakin interprets the growing rift between himself and Padme and the apparent warmness between Padme and Obi Wan as a scandal, turning his back on Obi Wan. In his anger, he goes to Palpatine (who is still his close friend and confident) and confesses that he is angry and hurt and that he's frustrated with the Jedi and with Obi Wan. Palpatine takes this chance to capitalise on Anakin's inner darkness to turn him. Of course, Anakin goes to Mace Windu, tells him about Palpatine, and Mace and the other three masters confront him. This is the part where we make this lightsaber duel much better, without slaying three out of four Jedi masters (and council members) in the blink of an eye. Despite his power, Palpatine is still an old man.
Anakin shows up just as Mace is about to gut Palpatine, duels Mace himself (because it's not a good Star Wars film without lightsaber battles) but because Mace is so exhausted, Anakin bests him. "What have I done," falls to his knees, tells Palpatine he needs to leave to come to terms with his choices. Palpatine allows this, because he knows that Anakin will be his in the end.
Anakin goes to Padme, confesses what he's done and how he's feeling, and she ends things with him. He blames Obi Wan, returns to Palpatine, Order 66 is executed.