In Crysis 1 and Crysis Wars, when someone was cloaked they would emit a fizzing sound. This way someone near by can be alarmed that there is a cloaker near by. As far as I believe this isn't present in Crysis 2.

Do you guys think Crytek should bring this back?

I definately believe they should.

so do i, cloak is too much OP from what i've seen on youtube, allowing to speed run and strength jump while in cloak just makes ppl be in cloak 90% of the game and needing a proximity alarm to detect it is far too much