Replace AoE actions with a stance that changes your single target stuff to your AoE actions.
It will be incredibly unconstructive, but... Ew. No. Heck no. The idea literally makes me shudder.

And more constructively, now: it seems hard to implement. There's no strict equivalence between mono rotation and AOE rotation in most jobs, because AOE rotation contains far fewer skills. Would the proposed change just be a sort of switch between several bar displays? That sounds more complicated than what we've got now, not to mention the lack of flexibility it implies in gameplay.