not necessarily. One could argue that aileron produce wing twist, especially on big wings. So if you are able to spread the aileron force on different parts of the trailing edge of the wing, you could possibly reduce the load on the wing.
As Rainboe said, there are different types of aileron on bigger aircraft, not only for redundancy, but also for aerodynamic reasons. Smaller aircraft can coordinate a turn only with ailerons and a little rudder, the bigger and faster you get the more problems you encounter during a turn. FBW doesn't replace aerodynamics, it's just to move the control surfaces.
Dani