We're talking about RPGs here, not character action games. Having complete control over 1 character while others are relegated to AI is going to create the possibility for errors and there has not yet been a perfect solution. Paradigms in FF13 did not account for advanced strategies in later parts of the game, and don't even get me started on the Tales/SO games (Zestiria's AI was ABYSMAL).
while action rpgs are not full action games it's not even fair to complain about how you have to put your other members on AI control. it's going to be limited at a base physical level. There's only so much you can control off a controller. this is like the definition of man yelling at clouds.