The sensitivity you need really depends of your way to move, people who will move only the fingers or eventually the wrist will still find a way to be accurate with a high sens and a small mousepad, and for people like me who moves the whole arm to perform a flickshot based gamestyle, we definitely need bigger space and lower sens.
It takes half a hour to go on a server and figure out what we need. Althought the style can evolve and we should still go on the server and see if our game has evolved so that we can adapt, elsewise our level is gonna decrease due to the routine.