People need to put these games into perspective.
The exclusives are usually designed to showcase the hardware and make the game look as amazing as possible. Games like Killzone 3, Uncharted 2, Alan Wake and God of War 3 all look amazing but have a range of tricks to acheive that look. They generally have smaller traversable areas, cheap (in terms of processing requirements) and clever effects, optimisation etc.
Crytek are trying to showcase their engine and are trying to pack as much into Crysis 2 as is humanly possibly to show off the tech. They don't just want to showcase pure visuals but the full range of capabilities in the engine to developers. This means larger areas, realtime effects, scalability, physics etc. Developers are more likely to see the full range of effects available without having to resort to the visual trickery typically used in exclusives. Crysis 2 still manages to look good but is doing more than the exclusives.
