Well, whenever you flash a new rom/kernel, it takes a good couple days to a week for it to "break-in" --- that's when you will see better battery life and what not. Flashing back to stock rom should be just as easy as when you flashed to 4.3.... Make a back up, wipe system & factory reset (from within recovery) then flash the stock back up (assuming you made one). Just make sure you have whatever you are flashing on your sd card before you begin the process