One thing i will never understand:
Why everbody think the AA-Battery is a bad solution for the controller.
For me it is the best solution for any controller because u can use rechargeable AA-Batteries (accumulator).
OK, these are not that cheap as simple one-way-batteries, but not very expensive at all and only 4pcs will last for a long time. A charger for the AA-Type (for remotes, etc.) should be in every household.
Priceless advantage: If the battery is empty, just change them with fully loaded ones and charge the emtpy. So u dont have to play wired, which u are force to with an in-build-battery.
This is called "cycle" and will also help to reduce waste.