I recenlty had an idea : why mask are in the same category as hat ? U can't have headphone and ninja mask for exemple, or scary mask with aureole, that's could be dope.
It's not ideal for performance, but also it becomes extra complicated when it comes to certain layering scenarios.
PokeMMO's chararacter customization is already quite in-depth in comparison to a lot of MMOs - and we already have some layers we've not yet released (i.e a coloured fishing rod).