XP increase potions, more "limited time only" cosmetics / mounts - saying this as I'm thinking this might be the only way to make blizz reduce the amount of mindless grinding at cap whether it is essences, AP, unlocking flying, or anything that did not use to exist before where we just simply needed to raid and do normal honor-based BGs to get better gear, simply enjoyed leveling alts without worrying too much about any BS mindless grinding at cap.