There is a very simple answer to why Revan is so loved. Spoilers just in case you never played KotoR.
It was because we were Revan! In one of the greatest plot twists in any RPG known to man, we were the very Sith we were trying to destroy. Then we spent years waiting for KotoR II, and we were the exile and found out that our character Revan waded out to the unknown reaches of the galaxy to fight the true Sith.
Then, we didn't know what that meant until SWTOR appeared. Only to have Revan return and have him saved and killed (well, not really killed) in mid level flashpoints.
So the answer is simple. A lot of us have a vested interest and connection to the character! Some of us don't care if Revan doesn't look exactly how we played him, we still lived his story.
This man/woman gets it.