Most satellite speakers w/ 4" and smaller main drivers tend to roll off around 150 -200 Hz (enormous overgeneralization here) even though they may list an 80 Hz frequency. That's why they tend to sound small compared to larger models.
So, a typical setup will have a hole between the crossover frequency (probably 80-120 Hz) and natural roll off of the surrounds. However, Audyssey and the like will eq each channel to fill in some of that hole. This does work pretty well, but the cost is greater power demands on the receiver and greater excursion and thermal power handling demands on the satellite speaker.
Is it worth it to have a large main driver in the surround? That's kind of up to you.