Ah crap, mine literally has this update queued and is just waiting a restart right now. I've never had to revert an update before, is it easy to do? I assume not if you're making this topic.
I see that the don't even make it easy to stop windows updates now. Seems you have to do it through the run command.
EDIT: Nevermind, seems to be easy to revert in the update history since there's uninstall options. Have you tried that?
EDIT2: Mine is also taking forever to do the update. So I may be in the same boat as you once it's done.