BF3 sounds great! Just wondering why they forgot that boots make noise too? I don't mind the knife, I like the way it works, but not everyone is as quiet as a mouse when they are running around behind you! If you're running around with squad sprint knifing people in the back you should make some noise. If your sneaky pete crouchy style sure, run silent.
Of course I don't mind it when I'm the slicer but if I had a choice I'd take noisy feet.