The left click is meh. Especially if you have a ranged weapon in hand. Wanna just avoid that demon? Nade to the face instead! Is there a way to mark more than one target? Since most times, I am the ONLY one doing the marking.
It's really this IMO. Too many times you get whacked from behind when you think you've cleared your backside. That chip damage adds up real fast. I do my best to keep the Psy clear so he can go ham.