Just some more information to consider about Longstreet as it pertains to this discussion. Before I get into specifics, we need to remember that what was written 10, 20, or 30 years after the fact isn't always the most accurate, and all of these officers and soldiers had grudges. Longstreet to a number of attacks against his character shortly after the war and said nothing, and then when he did responds proceeded to shift almost all blame away from himself and towards others, including Lee who was already dead, and couldn't defend himself. Early, Gordon, Longstreet, E. Porter Alexander, and even the staff officers who wrote after the war all had biases against other individuals in the army and these biases sometimes affected their viewpoints to what actually happened.
There is a belief that Longstreet was a "western bloc" general, but in a letter to confidant Sen. Louis Wigfall (who also was a western concentration supporter) he basically tells Wigfall that the AoNV can spare no men for the west, and the it'd be better to actually send men from the west to their army for the invasion. After the war in his writings his tune changes and he implies he was against the invasion and if it was to be fought it was to be tactically defensive in nature. That's not to say he was never against a concentration in the west, just that he plays a little loose with facts later on to put him in the best light, and honestly I get it, after years of Gordon and Early savaging him with relentlessly in the press.
As for the defensive nature of the battle, that went out the window when Stuart stopped his primary mission of keeping Lee informed of the AoP movements. After Longstreet brings Harrison to meet Lee, and Lee ultimately decides to concentrate at Gettysburg, the die is cast. Lee mauls I and XI Corps of the AoP, but they are able to fall back to high ground. I had mentioned in a previous post that on day 2 Lee's options are limited. Without Stuarts better cavalry brigades a movement to the right was out of the question, on top of the fact the road network didn't really offer much opportunity to move in the way the Longstreet suggested. That left 3 options, attack, retreat, or do nothing and hope Meade attacks him. With how well day 1 went, Lee's decision to attack seemed like the right one, and the original attack was supposed to be a flanking assault by Hood's and McLaws divisions, but when they get into position, The Yankee line wasn't where they thought it was, and it was getting late, so Longstreet with consultation with Lee come up with the echelon attack that goes forward that day. Longstreet led the attack in his sector brilliantly IMO, but Hill and Anderson let the army down, and the wounding of Pender causes the attack to falter.
In all my readings Longstreet does seem salty throughout Days 2 and 3, but his fighting on Day 2 was well led, though if he had his troops to move when Lee returned from visiting with Ewell, they may have been able to get into position an hour or two earlier, and that may have made a difference as they were also running out of daylight during the assault.
Day 3 Longstreet pouted even worse, and didn't lead the assault with any vigor, again I'm not commenting on how successful it could or could not of been, but most agree Longstreet led with no energy behind it. I don't think this takes away from him overall as a commander. Over the course of the war Longstreet was as good as they came. All leaders had good and bad days.