This was done in X-2, although it didn't have passive defense.A key problem Square-Enix has obviously been trying to deal with is that games have supposedly become too 'advanced' to allow Turn-Based battles due to them being 'unrealistic'.
FFX's system suited me just fine, and though I never played the sequel I heard it shoehorned ATB into it pretty well. One thing I've always wanted to see in an ATB system is for different attacks to consume different amounts of the ATB bar depending on their power. Better yet, some kind of passive defense that only stays active when your ATB bar is half-full or better. This way players are not compelled to attack the moment their bar is ready, but instead watch the timing of enemy attacks with their own. Also, either up the battle clockspeed a notch or allow multiple attack animations to play at once (unless they're Summons).
I see the commotion about the androgynous male lead. Look at the bright side in XIII: in addition to looking like a girl, the main character actually is one.