Suggestion: Slot based transmog

Would it be possible to change the current item based system to a slot based system,
where your item's appearance in a particular slot does not change (even if you equip a different item in that slot) until you change your transmog?

The issue names no files, tests, or entry points; first locate the current item-based transmog implementation and trace how equipped items determine appearances. Confirm the intended slot-based behavior with the project before changing anything, then verify that an appearance remains fixed when another item is equipped in that slot until the transmog is changed.

Written by the indexing model from the issue text.