I cant remember what RPG game it was, but I found it worked/felt really good,
was a third-person camera that hovered behind you, and its distance from you
was adjustable by mouse-wheel. No clicking, kind of.
But the important thing is that if you zoomed in close enough, it would switch
to first-person view. Zoom out and it would switch back to third-person view.
It felt smooth and easy. And no "reaching for the keyboard" clicks either.

Mind you, the game DIDNT have crosshairs, and projectile weapons forced
fisrt-person view whilst "aiming", so I dont know how the "feel" would carry
to a First-Person-SHOOTER. The game was some First-Person-Hack&Slash game.

Hope this helps.