What's your fetch schedule on your email accounts? Running live wallpaper? Did you check the task manager and see what's running?
So I did the following in the last few days.
Factory Reset
Charged battery past 100% with the phone off
Changed corporate email sync from continuous to 15 min.
Did not reinstall Yahoo apps.
Smart actions were enabled both times.
This resulted in a change from about 8-12 hours to over 24 hours.
I would recommend at the bare minimum to do a factory reset and try and "fully charge" it with no apps installed to see if there is significant increase in battery life before returning it. I ran with zero apps installed for a day or two and I immediately saw a difference. Some app may be sucking extra juice, but I have not isolated a problem app.
Having said that, while effectively at least doubling the battery life, I may try and return for a new one, "just because".
Hope this may help someone.