Some of my addons are for dinky things like gathering (thus making it easier to find concentrations of things), but that wouldn't impact me too much.
Banning DPS meters would be a dream come true, but losing DBM would be a nightmare since I usually play with no sound on (so I wouldn't hear boss related audio cues for abilities).
Now, if they started making more features that made addons moot (like the current questing system vs questhelper/carbonite), then I'd be all for it.