@Shoebox: Do you mean that because they will become more important they will soon have costume slots? Or because they will soon be more unique like weapons that they should not have costume slots? Either way, I do agree that weapons should not have costume slots, as this would be just plain screwed up. It would just look weird and not make sense for the most part. However, shields are very much like armor in the sense that you don't really do much but block with them and wear them on your back. There's really no unique sense to shields aside from the art, just like Helmets and Armors - which have costumes. This is why costume slots would be useful for shields, because it would still look fine (better), be more customizable, and make sense, all at the same time. Weapons, on the other hand, would not make sense to be costume-able.

Although perhaps costume slots on certain weapons of only the same design would work? I mean, there's certain models used multiple times just with different textures, like for example the Cutter -> Striker -> Vile Striker -> Dread Venom Striker chain. Perhaps someone could be wielding the Dread Venom Striker but have the Cutter as a costume because the green clashes with their outfit -cough-. Although I'm honestly not totally up for this either, it's just an idea. I think it would just get messy and confusing, especially since we can ultimately have 4 weapons equipped at once.

I also like the idea of hiding your shield from being on your back. I'd probably be one to always have it hidden, unless I could get my hands on a Shining Ward (apparently non-existent as of now).