Not sure if this would ever be possible, but it would be amazing if we could have the option to equip quivers and cloaks separately again. I know quivers used to be bags and not back pieces, but clearly they occupied a different visual slot on our character model from every other piece of equipment. Similar to asymmetrical shoulders, it would be really nice if we could equip cloaks and non-cloak back slot items together for transmog purposes.
Clipping would not even be an issue, enough items clip already as it is. I don’t think people would mind it.
I know we have a few options already to visually wear a cloak and quiver simultaneously, but that’s just it: we only have a few. There’s one artifact weapon, Thas’dorah, and two Trading Post chestpieces. The Sylvanas chestpieces can at least be covered by tabards, so they go with just about any outfit as long as the bandolier/strap and quiver don’t clash with it, and those are fairly neutral-looking which is great. But the artifact weapon only has so many skins, and they’re pretty much limited to high elf/blood elf aesthetics for obvious reasons.
I think this would be beneficial to other classes too, since we aren’t just limited to quivers for non-cloak back pieces. Wearing a backpack and cloak together would be awesome, as would any other non-cloak back item really.