Why are the sensors in the middle of computer mice, when they should be in front?

(M)oving just the forefinger — not the whole hand, or bunching all the fingers, but just the forefinger — actually makes the mouse rotate, particularly for left- and rightward movements. If the sensor is up the front of the mouse, that rotation of the mouse will give the user the desired outcome: the cursor will accurately move to the left or right, or back and forth.