Echoing what everyone else has said, and I'm sure its a real obvious thing to Mazzle, and he's simply moved on; I'd absolutely pay a subscription fee to have an always updated MazzleUI.
Such a thing might even persuade me to return to WoW. Losing this perfect UI was easily one of the largest contributors to me stopping playing WoW.
Really, Blizzard should pay Mazzle to write them a new UI
P.S.: Did you know Warhammer Online has a Lua UI scripting system? (Just kidding
)