I played it in SD I would agree with the 7.5, but in HD its a different situation, it actually makes it seem like a much "funner" game.
I would say its better than call of duty 4, and give it as much as a 9.5/10.
In SD it looks dark and dull, HD it looks amazing. Best ratchet of them all in my opinion.
2008 end of year predictions:
PS3: 22M
360: 25M
wii: 40M