I don't see how it'd make you a powerhouse. I'm not saying unlimited energy or fast recharging. The last battery is simply far superior to all other batteries. Meaning there's no reason to buy more batteries. You can just chow on power bars instead if you absolutely can't wait for the recharge. Which is a corner case, most of the time.
The most common ability to use battery on is the takedown. But using takedown when you have more than one battery full is a waste of a battery, since it kills that battery, that would have been better used on another power that might still allow regen.
It either needs all batteries to regen, but to take longer, much longer, or to allow takedowns to not kill the entire battery, so it can recover from infrequent use.