UE3 games do have higher CPU usage and are usually really well optimized (minus R6-Vegas) but I actually think it's to Crysis advantage to have a lower total CPU load because it creates a headroom for more physics. Lets say Crysis would use 95% of all CPU power you have and still would run the same framerate and same features, don't you think it would actually be worse? CryEngine2 and it's own physics engine might very well be more efficient than UE3+Ageia API but the only way to test it would be to build a similar level with the editors and test the limits of possible physic objects vs. CPU load.
I also think the framerate is acceptable for what is being rendered here. The amount of textures, polygons, shaders, realtime softshadows is just crazy and it's demanding for todays hardware, too demanding at VERYHIGH and even more so when you go beyond it with cfg tweaks.
I'm sure there is room for improvement and we will see it both from Crytek (they want to support the game for 2 years, lets hope EA lets them to do it) and Nvidia but only the guys themselves know how much but we can only wait and hope and I'm myself definitely looking forward to the next high-end card because we finally do need it.
Edit: Another thing that I forgot to mention is that UE3 uses a deferred renderer but I'm not sure what type of renderer CryEngine2/Crysis use.