a couple of people have been talking about advanced military comander (megadrive), haven't looked at it yet but it sounds pretty fun. i will have to check it out! so it plays fine on the GP32 then..?
another great megadrive/Genesis game is Herzog Zwei, "the first RTS" - I don't know if it runs properly on GP32 yet, I got it to load with gigadrive though. my favorite game of all time, MAYBE...
also you got Warlocked on GBC, and Heroes of Might + Magic GBC (too bad they never made GBA updates.. did they?) And Super Famicom Wars looks great but no finished translation patch.
Other (supposedly) great games to investigate are Earth Light 1 + 2 for Super Famicom, but again.. no patch as of yet, if ever, so it's all in Jap. Supposed to be in the vein of Military Madness (which i STILL HAVENT PLAYED EITHER!! GAHHH!) and I've heard great things about each.
Advance Wars was the most fun with a game I have had in years...