Heya!

I usually don't care about macros, but anyway =D
If I wouldn't care about macros, I'd simply press the Y button on my Rumblepad F510 (Xbox360 Controller) and switch between AoE [On/Off].

As a macro whore, I would do the following: Adding a "string type" to the variables of the /ac.

Examples:

/ac "Cure" aoe
/ac "Fire" aoe

For single-target on effect attacks:

/ac "Cure"
/ac "Fire"

I don't play Mage, as I don't like magic, but that's how I would resolve this.

See ya!