As I said by the past, there’s a problem with cosmetics.
Only the imperial edition cosmetics are done correctly, all others change the model used to a default one.
As a consequence, I use them only if it matches my current weapon.
I use cosmetics for the lwbringer shotgun, but won’t use them for the kantrael.
I use cosmetic for the brassed colomnus (hopefully, this is the one I prefer) but won’t for an agri.
On the idea of the OP, I would not be against this. Even if, for me, the most important is that models are really differents (and that’s why I use less and less weapons cosmetics).