I'm sorry, but I don't think Mr Hayashi, who produced and directed the game, would go on record saying "gee, actually, the game is kinda sucky-sucky". Not to say that it is sucky-sucky - it most likely kicks serious booty, but that's beside the point.
Also, I think if there is any type of game genre that can pull off 1080p@60fps, it's Ninja Gaiden, Devil May Cry or Onimusha-type games.
Basically, you are combining prerendered backdrops, some hi-poly set pieces and even higher-poly models onscreen in a small, confined area. For instance, when you go into a room in Ninja Gaiden, the game will actually load the "room scene". For the player, this means Mr Ninja has entered a room inside a castle; for the game engine, there is no castle at all. The only thing that exists in the game at that point in time is one room (with its associated prerendered backdrop, set pieces, baddies and of course, Mr Ninja. Everything outside the room is a black void of nothingness. This does not require nearly as much processing power, as, say, sandbox games like GTA3 or open world scenes like Oblivion. And also notice how the camera on Ninja Gaiden is fixed? For the very same reasons: One set angle (or a controlled range of angles) requires far less processing power than allowing the player to change the camera angle at will. By fixing camera angles you can also avoid having to render or for that matter create assets beyond what the camera allows you to see. Games like Oblivion don't have this benefit.
Just think back to the original Resident Evil on the PS. There was no way in a pig's ass that the PS could actually have rendered those backdrops, and they weren't - they were prerendered textures. The actual zombies looked like crap in comparison.
Of course the PS3 is capable of much higher poly counts per model, but the way the game is structured has not changed from the original Resident Evil, which if I recall correctly, pretty much set the bar and paved the way for these types of games. So for them to accomplish 1080p@60fps is not surprising at all. Given the nature of Ninja Gaiden's gameplay plus the sheer raw horsepower of the PS3, I would consider anything less to be a technical flop from Mr Hayashi.
