Visuals, as important as they are for some, do not trump function in my book. I'd much rather see a system where I can make mechanics of a weapon behave in a way that is more in line with my preferred playstyle. With actual effect on gameplay and not just "fire slightly faster, but have less ammo". Saay if you have a nail gun that can be made into spike/rebar shooter instead, making it higher damage per round and more accurate but with much slower rate of fire. Instead of taking 10 shots, you might do the same damage in 1. Event if dps is technically the same, spraying BBs at your mobs never quite compares to nailing opponents to scenery with one well placed shot.
I would be happy with stock gunmetal gray if it was a gun worth having.