It seems that opinion's change with each generation of historians. I have not read Foot's works in whole. I am currently reading Walter Geers Campaigns of the Civil War published in 1926, he goes into as much detail of each battle as I have found, quoting both Southern and Northern officers biographies and battle reports.
What is refreshing is the critical opinions of Southern Generals towards fellow CSA officers. I almost have to giggle when I read for the first half of the book, because there is nothing but disrespect for McClelland, until he is replaced by Burnside!
Geer writes;
Regarding none of the leading generals of the Civil War has there been such a difference of opinion as in the case of General McClelland; and after the lapse of three score years the controversy is not yet settled. As Cicero said of Julius Ceaser, "coming generations will dispute over him." To some McClelland is the "prince of egoists, the grand procrastinator, the timid and doubting captain"; to others he is a "military genius of the first order," who was "thwarted by an incapable administration and the intrigue of politicians."
Dr. McCartney writes "had McClelland never done anything else but organize the Army of the Potomac, and bring order out of the chaos after the Battle of Bull Run, his service to the nation would have been not far behind that of any of the Union generals. The weapon which Grant finally used to strike down the Confederacy was the finely tempered sword of McClelland."
So it would seem to me that while Lee was besting McClelland he was a unimaginative, timid leader who never committed his entire force against his enemies weakest point, even when he had Lee's battle plan in his hand, he failed to take full advantage of the circumstances. However, when the same people start writing about the greatness of Lee, there is a need to make McClelland look much better..
You can take from that observation what you want. Lee never had a problem reading Mac's every move, Lee dominated Burnside and Hooker. But he never could figure out Grant. The question then is, could Grant have preformed as well in 1862 as he did in 1864 and 65?
Grant takes much criticism for having "failed" at his earlier military career, but McClelland also left the military to pursue a civilian career. He only returned on the request of Gen. Scott. Once again the reality is that before the war there was very little opportunity to advance in the military.
There also has to be some consideration given to all the fine officers who were very capable rising stars that may well have out preformed Lee or Grant, but were cut down in battle. Ask any person who has been in combat and you will find out that there is no shortage of great leaders under fire, but many die with their men, before their leadership is recognized by higher ups, and rewarded by promotion.