Actually, McClellan was an excellent General for training troops. He had a serious flaw. He loved his troops to the point that he couldn't stand to sacrifice them at all. He was the opposite of Grant. From a modern war standpoint, Grant was an excellent General. He would sacrifice his men no matter how many got killed, to achieve his victory. it obviously worked. Lee was willing to sacrifice men, but only to a point.
Victory is the overall requirement of a general. Every decision one makes is going to cost some their lives. Had Grant not pursued victory at all costs the ultimate costs would have been higher.
How often have we heard the claim that dropping the bomb on Japan was inhuman and ruthless? In fact, doing so SAVED perhaps millions of lives. Grants refusal to be denied victory also saved thousands if not hundreds of thousands of lives.
He locked onto Lee like a python and squeezed him into surrender. That is good generalship.
It was the defensive advantage which cost Grant so many lives. Just as it did Pickett at Gettysburg.
McClelland's failure was due to timidity and hesitation not excessive humanity. Plus, he probably wasn't really that in favor of fighting the war in the first place being a Democrat.
"To be a good soldier, you must love the army. To be a good commander, you must be willing to order the death of the thing you love." -- Robert Lee.
If you honestly think that put in the same position Lee would not have resorted to the same tactics as Grant in order to win then you are belittling the man far more than you accuse me of doing.