If there's one thing the default UI does well it's take up large amounts of screen real estate while displaying the least amount of information possible (and looking ugly).
I'm confused by why did I see repeated references equating addon removal to an anti-botting measure or the suggestion that addons are cheating.
How would squashing threat and removing threat meters make threat management a skill? It would just turn into one big RNG guessing game.
Would I? Probably not. I love the convenience addons provide, as they let me do a lot of tedious things much faster (posting a lot of auctions without the help of an addon is a nightmare, for instance). I also loathe the look of the default UI, so not having my own fully customizable UI would be hellish. I mean, as it is, my account is lapsed, and likely will remain so until WoD launches or shortly before it does.