For Meade to die at this point, the battle's result wouldn't change, but the army would likely capture less men and supplies on the retreat. Slocum would by seniority take command, but Lincoln would not keep him around for long and someone more suitable would take control.
Sedgwick was very popular but not very talented, McClellan is always hanging around, and maybe if he gets another chance he might do better, but likely, Sherman takes control. He was not very busy in Mississippi at the time, and Grant could not be spared.
So let's say that during Pickets Charge a lucky shot from a Confederate soldier strikes Meade and kills him. Who would replace him as commander of the AotP? Does Grant get the job almost a year early or does someone else get it? How would this effect the rest of the war and when does it end now?
I suppose Halleck is senior and knocking about in Washington being irritating. Somehow I can't see a westerner sent directly east to take command. John Pope is still an unpleasant memory. How senior is Henry Hunt? If offered I suspect he would turn it down.
Speaking of seniority I am always irritated by the absence of an "army list" that will give me a list of seniorities for each year of the war.
As unlikely as it would be, a good TL would be for George Thomas to take command of the Army of the Potomac. Thomas vs. Lee would be a epic battle. Thomas would likely do much better than Grant did; he certainly would not have launched such a stupid attack as Grant did at Cold Harbor.
The next guy in direct command after Meade was Sedgewick, i think. And he was passed over in favor of Meade.
While the Gettysburg Campaign itself would turn out more or less as it did IOTL (none of the corps commanders would be any more aggressive in pursuit of Lee than Meade was), the butterflies would be pretty big. One thing is for sure, though, and that is that Meade will become the great Union martyr of the war.
The best corps commanders have been wiped out by Gettysburg - Reynolds is dead, Hancock is badly injured and now you have added Meade to the mix. Hooker and McClellan are politically impossible. Sickles would be a horrendous choice even if he wasn't injured.
Sedgwick,[1]
Slocum, Sykes and Howard are all singularly unimpressive. Warren might be ok in a commanding position and he was at the peak of his reputation at Gettysburg. But Warren would not work well with Grant when the time came. Humphrey is pugnacious if nothing else.
If Grant does go East after vicksburg, who replaces him in the West. Although we would all like it to be Sherman, I'll be honest when i think the seniority was Rosecrans.
I know the general feeling was that the army wanted McClellan back, but politics is going to keep him away.
Maybe Hooker? Course Grant might keep him out east though. Also if Grant does come east would he after getting his bearings start a campaign to at least be in Virginia before winter falls?
What about Lincoln's repeated OTL pleas for Meade to attack while Lee was waiting several days for the Potomac to subside so he could cross? The strategic situation was almost perfect for the North; a more aggressive commander (given a non-exhausted army, at least) could have made a huge difference.Further, I don't think that the pursuit battle after Gettysburg goes much differently - the determining factor is not the commander but instead the state of the armies - they are both exhausted as of late afternoon on July 3. It might be interesting to write a storyline about how the Army of the Potomac is howling for blood after Meade falls, but I don't see how they can accomplish much more than they did given what they have.
What about Lincoln's repeated OTL pleas for Meade to attack while Lee was waiting several days for the Potomac to subside so he could cross? The strategic situation was almost perfect for the North; a more aggressive commander (given a non-exhausted army, at least) could have made a huge difference.
So let's say that during Pickets Charge a lucky shot from a Confederate soldier strikes Meade and kills him.
Who would replace him as commander of the AotP?