I have hand tremors and it is difficult to steady the mouse for aiming.
MagnumBK, via World of Tanks forums
There is no one-size-fits-all sensitivity level. As well as personal preference, some gamers have a restricted range of movement so require very high sensitivity, others have difficulty with precision so require very low sensitivity, more still use alternative input devices (such as a head mouse) that have different sensitivity requirements to regular controllers.
Although PC/Mac operating systems offer sensitivity controls, these are within system settings which are only seen by advanced users, and consoles do not offer a system-wide setting at all. Different games also require different levels of sensitivity. Allow players to set it at game level, and offer a wide range of sensitivity. This applies to all types of input – mouse, touch, tilt, analogue stick, ideally gesture too.