I hate to get into realism since we are talking about CoD but amplifying the noise of one specific thing while everything else (including the exact same thing it amplifies in teammates footsteps) maintains the same volume level is just as unrealistic as complete silence. Especially when you consider the noises being gunshots, explosions, and aircrafts.
As for the whole crutch thing, it was the Amplify/Sit Rep Pro crowd who cried first during MW3 which is why it was in it's current state. And talking about dead silence not having a counter now when amplify has had zero counter as well until now. Dead Silence isn't going to win many gun fights for you, but if you're running Amplify, you should never die because you can hear anybody from an absurd distance.