I've suggested a cosmetic overlay system many times in the past, but it's largely been ignored. My idea would be just like Odyssey's: you can give any piece of gear the appearance of any other piece of gear you've acquired up to that point; perhaps barring weapons.
How difficult that would be to implement, I don't know. But it completely solves the issue of picking one piece of gear with a crappy aesthetic but good stats over another with an aesthetic that clicks with you but has poor stats.
They already addressed this somewhat by ditching levelled gear (thank GOD, I hated that in TW3), but they still have gear rarities. Preferable, but not perfect, and this idea fixes that.
Changing the color of the UI is pretty simple and it's even an option in quite a few games.
Alas, it won't be possible here. Confirmed by the FB account, believe I first saw the screenshot on Reddit.
Not worried, though. Even without mod support, changing the UI color will be a piece of cake on PC. So, whether they like it or not, it will happen.