Additional input now that I've been playing around with mouse aiming quite a bit recently: I believe that enabling mouse aim is greatly beneficial to the gameplay in Battle-based gamemodes, where being able to aim precisely makes the game more fun. In most other gamemodes, mouse aiming can also be a nice asset. The only circumstance where I'd rather have mouse aiming turned off is in smaller teamgames, especially 2vs2s/3vs3s in CTF, where good communication and quick movement are key to victory. I find it difficult to send CTF codes via teamchat whilst simultaneously fighting off enemies with the mouse.