You're retarded for thinking it's a bad thing in the first place. First, if your controller only has a built-in li-ion battery, it will inevitably go bad and you'll have a hard time replacing it like with the PS3 controller. Second, by having support for regular AA batteries, you get to have replaceable batteries without getting locked into the vendor's ecosystem. Get four Eneloops and you can quickly change them mid-game without having to play wired or waiting for the thing to charge up.
Now, if MS manages to keep that, and make the controller serviceable, AND have the analog sticks user replaceable, AND GuilKit makes Hall effect analogs for it, then we will have a very decent controller for PC gaming straight from Microsoft, assuming that by using recycled plastics they haven't made that thing destined to fall apart in years from the time you buy it.
The only thing I'll admit is that having the batts bulge out on the X360 pad was dumb. But having that little carrier box for AA's and being able to quickly load up a fresh set mid-game was a great idea and it sucks that they haven't tried to do something similar with the XBO redesign. Or even a battery clip so they stay together to quickly load them in easily.