Coming from Sakurai's bi-weekly feature in Famitsu...

"I was amazed at how, even under the limitations of there being only one party member [in Lightning Returns], [the ATB system] has evolved. It's easy to pick up an already released game and simply enjoy it, but in order to generate entertainment, you need to keep your eyes peeled. I was reminded that if you take what seems natural for granted, nothing will evolve or change for the better."

Looks like the battle system helped Sakurai to look at his own work from another perspective. As long as it's helping Sakurai in his own work, I'm down with it!