I really think Sit Rep Pro, should make sound enemy footsteps as regular on Dead Silence, and Louder Without it.
UPDATE: Well i see in the Hot & Fixes Section they are working on the next TU where they maybe add "Sit Rep Pro" will counter "Dead Silence" you will be able to hear your enemies at normal volume steps.
"Dead Silence/Sit Rep Pro functionality fix."
Extra: Petitions for next COD, here. http://community.callofduty.com/thread/200423045