Would it be possible to mod an ETW type diplomacy system for MTW 2 or is that hard-coded beyond any possibility?
Yeah, I've started to notice that myself and am rather puzzled by that. Valve has been very open and supportive of the mod community and look at what it's done for the commercial and critical success of the Half-Life franchise
Companies like ID software even released the source code for their older games like Quake
It'd be nice if CA released some type of official editor or SDK for their next game.