Not sure how difficult this would be, but it would be fun to have nonvehicle companies like BlasTech and Merr-Sonn Munitions as playable, and have those planets be able to construct and sell weapons just as say SoroSuub or KDY can make and sell ships.
with that, perhaps guns could have stats too. So like say infantry of course has the base stat, say [insert pistol here] ups infantry ratings by 3%, but [insert rifle here] ups then by 5% or what have you