Same problem, narrowed to gmail sync
I have experienced this same problem with shortened battery life and phone heating up. I was not able to pinpoint to that update, but sounds about right. I have narrowed it down to sync'ing. If I disable sync, the phone behaves as before (similar battery life as reported in the first post). When I enable sync and look at the gmail sync settings, I can see it sync'ing over and over again. It never stops (the little sync icon never goes away) unless I just disable sync altogether. Facebook seems to be sync'ing ok.
Not sure how to zap the gmail settings back to initial to start over.