I have come to a realization after reading niggers complaining about how dolls don't use their guns that much in the sequel.
Almost none of the skills on GF1 have to do with the guns themselves. All of them buff the dolls. Raising evasion, grenade launchers, damage up (which make no sense for guns). The only skill I can think of that has anything to do with the guns are the ones that relate to ammo types, like CMS.
This is because guns are fundamentally boring to make RPGs around and give very little room for creativity that isn't special ammo and maybe different attachments.