I think there should something be done about the AI of short ranged air anti air units. Both phoenix and scouts tend to ignore air units, if they are behind ground units, even if the phoenix have no energy. I think this does not occur for corruptors, because unlike the phoenix, they do not even use their skill against ground units (or even if they do, they ignore them after using the skill).
So a solution would be to let those units attack air units, if those are in a certain range, even if there are ground units that are closer. As I have no experience with the editor I do not know, how this can be done, but I hope I have described it sufficiently accurate to understand.
I do not know, whether the priority has been fixed for scouts, but protoss anti air still patiently waits in front of ground units to get killed by vikings or simply ignore medivacs and ravens.