RPG rarely get high score even when they're critically acclaimed, I'd say a high 80% would be considered a critical success and very likely to happen.
My favourite RPG of all time is Planescape Torment from Black Isle, critic could not stop raving about just how damn good that game was (and I agree) but it still only got a metacritic score of 91.
If this game 'flop' sale wise, I will burn my copy of LBP. :p