As it is now in the game, you have to use two hands to cast an AoE skill. That can be very disorienting, especially if you need to spam it really quickly. Most other games allow you to press the hotkey twice; once to activate it and second to confirm the spot, instead of having you press the hotkey then mouse click with your other hand.
I suggest adding the ability to cast and confirm AoE targeting location, with the same hotkey it's placed on OR allow auto ground targeting (allows you to cast an AoE with one hotkey press and places the AoE wherever the mouse pointer is.)
If someone wants to, I'd love an addon to fix this, I couldn't find one for it, saddly, but I'd rather Zenimax fix dumb stuff like this instead of relying on addons, but who knows how long that can be.