I hate crouch toggle and it should have been made an option like aim down the site toggle is.

Not sure why this was left out, was also left out in Homefront aswell. You guys working together? Both games seem to have the same crappy "feel" to them

If you use the Crysis 2 graphic modifier (search for it, can't remember the exact name), there's actually an option there that lets you turn it on.

Crysis2AdvancedGraphicsOptions.exe

Google for it.

I think there is an option for it some where. I have mine enabled, but I did use the graphic modifier that someone made for the game.

Go to the main menu, I did it from there, (I think).

But aren't the autoexec.cfg settings ignored for multiplayer!?

An InGame option is definitely the better choice.