In order to keep the community focused on just one modding area based upon the same engine version, we decided to make the AI in Crysis Wars available again to allow singleplayer levels to work and concentrate on supporting this game with editor and SDK. Together with most of the assets from Warhead which are included in Patch 1.4 we are confident that the community will benefit the most out of it by keeping singleplayer and multiplayer modding and level creation to one game.
So, previously the multiplayer portion of Crysis Warhead called Crysis Wars is getting patched to allow single player mod/map functionality. You won't need to have the "Warhead" single player portion installed if you want to create single player maps as they're "Turning on AI" functions in Crysis Wars.
This is a good thing, Crysis Wars can be installed as much as you want without worry of DRM activation limits, so even if you've burned through your activations for whatever reason you can install the Crysis Wars disc to play custom single player maps and mods, along with multiplayer ones too.
It might have been slow coming but Crytek still outshines many other game companies with their support for the community.
more notes about the editor on their dedicated modding site.
http://www.crymod.com/thread.php?threadid=45219