Instead of having to hold down the auto target key (Left Shift) by default, I think it'd be ergonomically helpful to have an option where you can use it to toggle auto target on/off. I know you can toggle it on/off from the menu, but it's not convenient to do while you're in the middle of fighting things, not to mention it gets tedious to do that every time you switch your weapon.

An example: My main weapon is a sword and I like to have auto target off since it sometimes mis-targets when too many enemies get clustered together. Using my gun, however, I find that using auto target is too helpful to not use. Right now I just hold the auto target key while using the gun. It works, but I find that after a while of switching back and forth from sword to gun, the finger that has to hold that auto target key down starts to feel it. A toggle option for auto-target would save some wear and tear on my fingers.

As far as implementation, a simple check box that enables/disables toggle behavior in the key bindings section next to auto target? Then you use that key to toggle it on/off...left shift by default.