I had something similar happen on my Nexus 7. A reset seemed to do the trick.
I've definitely notice a decrease in battery life with the new update. My commute to/from work lasts about an hour each way; during that time, I read the news on Flipboard (~40min of my commute), and listen to music on Pandora (the whole commute). On auto-brightness pre-update, my battery would be around ~80% when I got into the office. Today, it was at 67%. Pretty significant IMO. I'll see if the same happens tomorrow. In the past 2.5 hours, I've only checked the screen a few time for texts, and the battery is already down to 48%. Without a charger at work, it would definitely be dead by the time I got out. I know I had better battery life pre-update :/.
I had my DNA replaced, because it took me half a year to find out my old one was a dud. It had pretty bad problems with battery life (and GPS) too--if a reset doesn't fix your battery consumption, I'd try to contact customer service before your warranty expires (if it hasn't already).