Change "McClellan" to "Meade" and you've just described Gettysburg. Was that a draw, too?
If either Grant or Sherman were in command at either Antietam or Gettysburg, the Army of Northern Virginia would have never made it back across the Potomac.
It would have been one hell of a fight, but the war would have ended that day, and tens of thousands on both sides would have bee spared.
This goes back to the points I was making earlier. Lee was the best of the Napoleonic commanders, and every other Napoleonic commander he faced in the first 2 years couldn't hold a candle to his genius. Grant and Sherman, transcended Napoleonic tactics and understood it was not a Napoleonic war. Modern war was not about "winning the field". It was about destroying your opponents ability to fight another day. They didn't get it all right, but the fact is they were each 50 years ahead of Lee in strategic thinking, and won the war as a result.
Perhaps the fact that their early military careers were short and relatively unremarkable indicates that they didn't completely accept the military orthodoxy of the day that Lee exemplified and his early opponent tried to compete with.