I really dislike vanity armor slots, but... I'd love some way for crafters to recraft existing sets into any style learned!

Perhaps not in the "fiat" way of the current "imperializing" (just select "convert to imperial" from menu), but... requiring some crafting! Use some materials! With a destruction chance like temper improvements, perhaps depending on total crafting skill, that can be raised by using more materials... give people a reason to burn through their stack of style material! And keep the rare styles rare that way as well.