I don’t know if a feature like this would be useful in practice since zombies are almost always on top of you, but I figured having the option wouldn’t hurt.
The idea is simple: when you hold this button down, the camera moves away from your character based on the position of your mouse on the screen. The more centered the mouse is, the closer the screen and cursor is to your character. If you drag your mouse to the right, the screen moves to the right relative to your character and the cursor moves to the right relative to the screen. I suggest this because it was invaluable to me in Hotline Miami (which is what I’m stealing this suggestion from), since it lets you extend the area you can see (and, for me at least, tended to feel better for aiming).
This could be done by moving the special ability button to Q and having right click extend your view more towards your crosshair, imitating aiming down your sights, and possibly giving you a tunnel vision like effect around your crosshair.
I’d like to see something like that, because I find myself running into hordes of zombies I can’t see due to lack of view distance, even when I scroll away from my character.