bsieker -
The difference is the level of protection (which in this form, non-FBW aircraft don't have in the first place), and the amount of "smoothing" the computers do to achieve the desired trajectory.
Ah.....but my "old" airplane, along with others with 'conventional' controls, HAD this protection: it's called Design Maneuvering Speed; the speed at which application of FULL available aileron, rudder or elevator will NOT overstress the airplane. It approximates Rough Air Speed.