just for consideration, a possible tweak to gdi that would leave things much as they are, but allow for some kind of reprisal ...

allow a grabbed player exactly one attack of any type against the attcking player without respect to either player's gdi status

this allows a sharp retort for a grab, but gdi still prevents suiciders and the rest ... probably just means that you'll catch a NM or CM for each country you grab, so that might give an advantage to all-x, but it might feel more satisfying as a war game ...

with respect to giving non-gdi some kind of compensating advantage, maybe just award 2 to 4 bonus points per day ... i think this would be enough to push players to delay gdi as long as possble, perhaps opening up the game a little

cheers!