The only way I see something like this to work is a separate tool client for creating models, textures and etc.
I mean doing something new in it to submit on a community vote or directly to devs to decide, Basically something like Valve with CS:GO or Warframe devs were choosing fan made skins in their workshop to add later into the game.
We could have something like that, would be a win - win, since it gives LO free labor XD