I thought Lee was a tremendous general, but don't understand his decision to send in Pickett at Gettysburg.
I know that Longstreet took too long to coordinate his cannonade against Meade, but don't think it would have made a difference. The Union Army was too well entrenched.
Lee sent Pickett's Division and elements of two others across the mile-wide field at Gettysburg because 1) he thought that the Union was weak in the center because of his previous heavy attacks on the flanks, and 2) because his soldiers had in fact ruptured Union lines during full frontal assault before in the past, most notably at Gaines Mill in 1862, and during the last stages of fighting only six weeks earlier at Chancellorsville. He thought they could do it again.
As for Longstreet, he was in a snit at the time and dragged his feet in carrying out Lee's orders, wasting valuable time in the process.