I wanted to address this. I feel the cursor clickboxes for players and NPCs is way too large. This is also true for action camera mode.
I ran into a few instances last night where I was trying to click off of an enemy so I could use a skill to disengage a fight, but I could not click off of the enemy no matter how many times I actually clicked off of the enemy. It would not deselect that target, and I ended up using my skill to close in on the enemy instead of disengage on the fight.
I would definitely look into making the clickable boxes around players and NPCs much smaller so that split second tactics like disengaging or retargeting a different enemy could be possible, as this also gets in the way of being able to click another enemy on the fly.
The greatest enemy to improvement, is ignorance. But the desire to learn will cast ignorance into the fire.