Yes, the way your friend's Supers are acting is correct.
If the m'switches didn't trip until the stick hit full travel it would feel *very* unresponsive, much like how a leaf joystick feels when the leafs are bent too far out of adjustment.
On the other hand, if the stick travel was just long enough to trip the m'switches, then the joystick action would feel very truncated, much like a Suzo 500 (which takes quite a while to get used to!).
Some people bend the levers on the super to adjust the amount of diagonal contact, but I wouldn't mess with the joystick unless you are really having problems with it, it sounds correct to me.