World of Warcraft calling curtains on combat-based UI mods (AddOns) has been a bit of a mixed bag—while I'm personally more than fine having a class I don't need constant auditory pings and klaxons to play, there have been some missing functionalities and hiccups along the way.
One element of this is, at least, somewhat understandable: Blizzard isn't able to pre-empt every customization desire of its playerbase with nearly the same rapidity that an enthusiastic modding community will, which was one of my fears back when Blizzard first announced it.