So long as we are talking about Apparel, one thing I would love to see is to the magic slingers. Honestly, I don't think I've found a game that presents Wizards apparel with some serious robes, cloaks and hoods/hats and I think Staff's with multiple functions are missing (Think of the old Staff of the Magi). And would love a progression of robes just like a progression of armors. Some with single and some multiple benefits depending on legendary.
I've been a fan of high fantasy (example Lord of the Rings) and wizards in D&D landscapes like Dragon Lance or various wizards as found on Pinterest. Different artifacts that can be used other than wands and staves too. Such as orbs, pyramids, magic swords with spell capabilities, etc. Get creative.
