- Monster AI will operate under a FFXII-style 'gambit'-type system. Likewise, Chocobo AIs will operate under something similar.

For Chocobos: Awesome.

For Enemies: Can someone explain why this is fundamentally different from enemies in any other game?

If you are not familiar with the gambit system, it is basically XII's way of assigning certain actions based on conditions your party member encountered, by way of If/Then statements.

ie.
Your Party
(If) Vaan's HP < 30% -> (Then) Ashe cast Cura
(If) Vaan's HP = 0% -> (Then) Ashe cast Raise
(If) Yiazmat has Reflect => (Then) Vaan cast Dispel

This can also be applied to an enemy, say Ifrit or Garuda.
(If) Ifrit's HP = 50% -> (Then)Cast Hellfire
(If) Garuda's HP = 80% -> (Then)Release Plumes
(If) Garuda's HP <= 40% -> (Then) Immediately cast Aerial Shriek

You get the idea. While this is an extremely basic example, this is arguably the thought process people use when deciding what to do in a game, or any situation for that matter. It is also the types of conditions and algorithm structure(albeit more complex) that determines enemy AI.

So my question is why is enemy AI being changed into something that is essentially the same thing, and perhaps even simpler? What am I missing?