Do you think the newer device will have worse battery life
No, but it'll likely be more variable than current tablets. Playing Quake 3 at full blast while watching movies in the background and throwing files around WiFi and Bluetooth is likely to result in slightly shorter battery life than using a current tablet at full tilt. On the other hand, battery life at idle will be significantly improved.
When everything's said and done, battery life should be slightly improved on average.
