Speaking as a controller user, I find that there is no need to remove the AoE toggle to "free up" buttons. I have the AoE toggle set to my Square button (using a PS3 controller), and have never felt that it was a "wasted" button or that its preventing me from setting a more important function to that button.
I like the idea of AoE specialists, and even like the idea of "aga" spells, however as mentioned this would clutter the skill bars and take precious action points to achieve in any traditional sense.
Now that doesn't prevent them from being creative, for instance, you start with "Fire" that does not have the ability to AoE, and you later unlock the AoE for that spell, or equip the AoE (Materia!), or some other such device that would enable the AoE toggle for a (or all) spells.
Its not just one slot, its one slot for every single AoE skill we have. This would drastically reduce the number of skills we have per bar and is just generally a bad idea.
Other than "it uses a button I would rather use for something else" there has not been a viable argument for the removal of the AoE toggle UI.
Your arguments as they stand are about the mechanics of AoE skills, not the toggle. Wanting the AoE skill mechanics to change is something entirely different. I agree that AoE's should cost more MP and/or do less overall damage/heal, take longer to cast, etc...
None of these require the removal of the toggle UI, just the restructuring of how AoE's work and the cost to toggle. The toggle UI is a great addition to the game and makes using a controller a more enjoyable experience.
