There's also
WUU (WoW UI Updater) to
checkout that supports multiple sites,
and a few excellent meta-lists like
wowmods.
If your users are so lazy that they can't visit a couple of their favorite addon sites every other day
direct them to one of the above.
Note: WoWMods is just a meta-listing of updates, you still need to visit the respective site (wowi, curse etc) to get addon details and download.
Edit: I realize I didn't reply to your query directly but if your predicament comes from users
requesting you "make it Ace'd" or some other silly demand so they can one-click update through WAU,
you could point them to the tool above that supports 1-click update for your addons as is.