My brother played basketball for 3 years with a SEVERED, not torn ACL. His knee would dislocate a few times a year, but he never missed a day of work. The doctor told him it wasn't completely necesarry for everyday life, but for playing sports he should fix it.
I would personally like to see the displacement for 4 strokes adjusted to make the classes a little more even. Say, 200 CC for 125 class and 350 CC for 250 class. The advantage now, especially in the 125 class is ridiculous. It's just coincidence that most of the top riders in the 125 class have ridden 2 strokes. Although with Stewart it wouldn't matter what he rides. CC for CC, there is still no comparison, 2 strokes rule.