The majority of those movies are pretty damn mediocre, I don't see how you can call 12 of those great roles.
The only ones you could really argue for are:
-Fight Club (let's be honest here, Norton gets wiped of the screen by Pitt in this)
-Primal Fear (Good performance up until his characters starts showing the "crazy side", after which his credibility goes out the window)
-American History X (too sentimental and preachy for my tastes, the movie I mean)
That's four and that's being pretty generous.
The Score is awesome. It's a HELLLLLAAA good movie. His acting is on point. I def thought he went full-retard
i've never seen edward norton be anything less than fascinating, regardless of the strength of the movie. never.
i'm sure he's not for everyone... that's okay. but there is no question in my mind that he's a very good actor who can play lots of different roles. some personal faves: painted veil, the illusionist, primal fear.
also, there would have been no point if he had upstaged brad pitt in fight club. the whole idea of his character was that of repression and playing it safe. to criticise him for being mundane in that movie is silly, IMO.
American History X
Good or mediocre movies:
Keeping the Faith
The Score (Norton does great, the movie is just decent)
25th Hour (Norton does great though)
Death to Smoochy (Norton awesome again, underrated movie)
Down in the Valley
The Incredible Hulk
Bourn Legacy (closest one to making my "bad" list)
Leaves of Grass
I haven't seen his other movies entirely. A few gems and no bombs as far as I can see. It has been a while since he has been in a great movie though, so the OP isn't too far off.
I don't care what anyone says, Edward Norton is one of the best in Hollywood, and IMO, the most underrated in the industry. Dude doesn't receive nearly enough credit for the caliber of talent the guy truly is.