Awesome idea... I'm on it.
...plus I find sometimes GAE doesn't pick up my target straight away. So I usually click more than once anyway
This is not a problem unique to GAE, skill cycles can't be interrupted, so there is a delay before the new command will begin, you
can trust that they will do what you asked at the next available opportunity, clicking again doesn't actually help, be patient
I think the double right click to target all of that type (within a certain radius, as per selecting your own units) would be handy, but I'll just start with the drag select and think on double click thing (and consider thoughts from anyone else who cares to express them...)