Assault class skins - more than other classes

Hey Dice,

Why the assault class have more skins than other classes? 
Why we can't use skins we've bought on other classes? They should be universal. There are many skins that looks nice but I dont want them because they are assigned to specific classes.

Such a shame that customization from BF5 wasn't implemented in new BF6.. it was the best and gave much more :/