Auto hotkey... It's out there and you can program conditionals with it or just a straight priority. It is also undetectable unless you create an actual bot.
This, or something similar, is what so called pro's use today. Of course they don't want a regular ingame macro system because then all the plebs would macro too and they lose some of their advantages.
An ingame macro system would level the pvp&pve field a bit and make the game less of a chore for several classes.