I personally favor a broad umbrella definition for RPG. Mainly, it's no fun to split hairs on fringe titles. But also some "action adventure" games like Red Dead Redemption have far more compelling narratives than a good chunk of classic RPGs.
So if Mega Man Legends is an RPG, then so is SotN.
Assassin's Creed 2 is so damn good. I've never had so much fun doing the simple collection stuff.
I think I might like it better than RDR actually. I'm not deep into the story yet... but the way John was led by the nose in RDR really set me off. What I mean about 85% of missions started w/ John approaching someone and going "Do you have ____ for me? I ain't got all damn day." Then the NPC would say, "Sure Mr Marsten! Just help me do _____ ." What a shitty way to advance a story, especially one filled w/ great characters and actors.