We don’t want weapon skins in EC to be purely aesthetic (as in, you could look at a weapon and not know what it actually is). Mechanics like that take away from the feeling of a world.
Instead, we want appearances to have meaning. It’s particularly bad in a PvP game, wherein it’s nice to be able to know what the weapon is you’re fighting. That doesn’t mean we can’t have things like color-swaps or adornments on weapons though. Our rule of thumb is to use common-sense.