I could see Lee going to 3 corps in the winter of 1862-63 if D.H. Hill was not an obnoxious twit (he was senior to A.P. Hill). His inability to get along with others killed his career in the AoNV.I have often wondered (as a what if) that if Ewell had not lost his leg whether Lee might have gone to 3 corps earlier. He believed that each corps was too large for one man to conmand and control, and I believe the 1862 Maryland Campaign was a trial of sorts for McClaws. He failed Lee's test.