Hmmm. I agree this may be good for some but it would force me to use a mouse. I play keyboard only(not even mouse) and it would be nearly impossible to implement this without requiring the use of a mouse or controller.

Having just an indicator (hopefully not too visually intrusive, maybe toggleable so people who don't want to see it don't have to...) that shows the actual AOE area for an ability would be kind of cool.