When both M1 and an ability key are pressed, the current behavior results in stutter-stepping. I would like instead of the ability key overrode M1, and the character stood still constantly casting/attacking/waiting for cooldown.
This is the technique I use often in PoE to help reduce RSI from clicking; M1 is bound to move-only, and is essentially always held down. I hold down ability keys as needed, and on release my character is already moving to the next pack due to M1 still being held.
The current behavior has become especially problematic with the new rogue flurry skill (non-channeling). With M1 and the ability key pressed, the rogue fires only 1 arrow before taking a step, reducing the overall DPS.