I was going to post this myself, actually this isn't just for spells, but I would include attacks as well.
The issue with attacks, either magical or Melee/Ranged standard Attack Actions, is that it is too easy to click the ground instead (which sometimes you might want to do), whilst trying to position the character in the move part of the attack. Being able to select the portrait of the enemy in question within the Initiative bar (highlighting the 3d Model as you hover over to ensure you have the right opponent - maybe even move camera), would mean the AI would be responsible for taking the directest route (if movement is needed for melee attacks) and taking the swing. The % to hit should appear just as if you were hovering over an enemy in the normal manner.
Yes it might not be the path I would choose, but it would be a trade-off if I wanted to ensure the attack wasnt wasted by a misclick.
You could simplify it by not allowing movement via this method.
It also improves targetting choices, because by selecting the enemy via the initiative bar you see more easily who has what health and can attack accordingly.