An idea for the next crysis:

Why not build a mode to have time control into the suit. You can go back in time for a few seconds, to change your tactics or to dodge the bullet that just killed you. Or a slowmotion mode...so you have more time than your enemies.

Errr.... Timeshift? Prince of Persia?

Never played it, heard of it and indeed now that you mention it...
Forza has also a replay function

would be impossible for MP, in SP it could be useful. But so far, the Nanosuit was at least a bit authentic, but how would you explain, that Crytek ( or whoever invented the suit) now is able to go back in time? If they can do this, they could simply travel back in time and hinder the ceph from uprising.

They can go back juist a few seconds. The already upgraded the suit so it could be done with ceph technology...

I don't think it's a good idea... The game is designed around only a slight amount of Science Fiction. It clearly is trying to be realistic, while having this supersoldier feeling. Travelling back in time would be too much futuristic.