Once again, let's have a look at the period between July 14-October 1, 1863.
The Army of the Potomac took approximately 1/3 casualties at Gettysburg. Those men do not magically re-appear. Wounded men need to recuperate, new men have to be recruited and trained, and they need to take the field. These things take time.
In addition, after the battle, 16,000 men were taken from Meade and sent to New York City to put down the draft riots, where they stayed for a while. Further, you had quite a few men whose terms of service expired during the summer of 1863, and they took their discharges and went home.
Thus, by August 1 or so, Meade had only about 45,000 effective men in the field. Meade was chafing. He WANTED to attack, but Halleck, concerned about the lack of manpower, ORDERED Meade to stand down. Let's keep that in mind.
In fact, once across the Potomac River on or about July 17, Meade turned hyper-aggressive, and pitched into about 1/3 of the Army of Northern Virginia at Manassas Gap, also sometimes known as Wapping Heights. Meade nearly cut-off Ewell's entire corps and nearly destroyed it. Ewell, however, escaped across the Shenandoah River to safety, with the Army of the Potomac in pursuit. This is the precise time frame when troops were being taken from him to send to New York City, and Halleck felt it necessary to rein Meade in. Consequently, when the armies returned to the banks of the Rappahannock River--from whence they had begun the campaign--Halleck forced Meade to wait.
Mix in the fact that the three most aggressive corps commanders in the Army of the Potomac were gone (Sickles--without a leg, Hancock--severely wounded after his magnificent performance at Gettysburg, and Reynolds--dead), replaced by the likes of William Hays, John Newton and Blinky French (about whom I often say that the only aggressive move Old Blinky ever made was on a whiskey bottle). Indeed, only Slocum, Sedgwick and Uh Oh Howard had more than a couple of weeks experience commanding corps. Slocum earned the nickname Slow Come for good reason and Howard, well, one only need study his performances at Chancellorsville and on July 1 to get a good sense that this man had reached his level of incompetence for Peter Principle reasons. That leaves Tardy George Sykes (a corps commander since June 29), Hays (July 3), Newton (July 1) and Old Blinky (July 10), with no experience to speak of. Hays was soon replaced by Warren. Newton didn't last long either.
These guys needed to get some experience and to get their feet under them in corps command. They had limited ability in the first place, and to expect too much of them is not reasonable. An army commander is only as good as his subordinates. If you need proof of that, have a good, hard, long look at the Army of Tennessee. The troops sent to New York eventually returned, but then the 11th and 12th Corps were detached and sent to Chattanooga, never to return, leaving Meade with only about 60,000 men. Conventional wisdom was that you had to outnumber the enemy by 2-1, and Meade's army was no larger (and at times, smaller) than Lee's. Not until the spring of 1864 when the 9th Corps was attached to it, new troops mustered due to the draft joined the army, and the arrival of troops stripped from the defenses of Washington, DC and other coastal areas did the Army of the Potomac receive any significant reinforcement to regain its numeric advantage.
French, in fact, did so poorly during the fall of 1863 (and especially at Mine Run, where he was insubordinate and rightfully drew the Old Goggle-Eyed Snapping Turtle's ire) that the Third Corps was merged out of existence early in 1864 just to be rid of Old Blinky. For those who don't know this, I am researching to do a book-length study of the Mine Run Campaign, so I have a pretty good handle on just what a poor job this drunken lout did during the fall of 1863, but he outranked nearly everyone in the army, which made it exceedingly difficult to get rid of him.
Meade himself knew that his army was not yet ready to take the field in a major campaign during the fall of 1863, which is why he resisted the idea. It took a direct order for him to undertake the Bristoe Station Campaign and the Mine Run Campaign. At Bristoe, while he roughed up Hill's Third Corps rather badly, had a large-scale engagement come about, Lee was on familiar ground. At Mine Run, a full-scale attack would have been a worse defeat than Fredericksburg, and Meade deserves credit for calling it off once he was alerted to the danger.
Meade's real downfall was the chaos created by Dan Sickles through his anonymous Historicus articles and the subsequent witch hunt of the Joint Committee on the Conduct of the War, which was looking for a reason to crucify him. Nobody needed that distraction, and having all of those backseat drivers inevitably meant that it was impossible for Meade to please them. They had such unrealistic expectations that he never had a chance.
Finally, let's also remember that Meade had never wanted army command in the first place. He was ordered to take command, and as soon as the Battle of Gettysburg was over, he tried to give it back but was rebuffed.
The man clearly had his flaws, as does every human being. However, I tend to give him some slack because of the circumstances, and, at the end of the day, he fought a brilliant battle at Gettysburg and won a decisive victory under some of the most difficult circumstances imaginable.
And, just a parting thought: until the final campaign in the spring of 1865, when the Army of Northern Virginia had been stretched to its limits and worn out, just how many battles did Grant win in the East?