I have to weigh my words here Let me explain how PC controls currently are (and how they will stay unless playtesting shows us it's a bad idea):
You control the camera using FPS controls and move with the WASD keys - that means there's no mouse cursor on screen.
So I guess that leaves the mouse buttons for primary and secondary skills.... Does the scroll wheel cycle through available targets in combat? Or is there no targeting and you have to move to an appropriate position and just attack?