AoE Cast on Target?
Use smart cast (its in the options) then you just have to point at your target with your mouse and click the skill.
It might seem a pain at first (it was when I started using it) but now it’s amazing for aiming stuff
Be warned, if you use the mouse to move around, smart casting can be infuriating.
If you use the mouse to move you are probably best served by placing the mouse in the middle, then smartcast works like a crosshair would in an action mmo :p
A side note, but don’t forget you have weapon-switching. I love using staff as one of my necromancer weapons (and it does look cool!), but I rarely use it when running around by myself. In groups, necro staff is excellent. So, if you’re willing to only have it some of the time, you can compromise!