I don't think the speed is at fault. The problem is that it is so "easy" to produce the speed. Modern sponge bats produce speed too easily. The current trend is to even thicker sponges, which will make the problem even worse. Since the bigger ball has not had the effect of curbing the speed in the sport, maybe it is time to consider then next step.
Two options come to mind, the first is to limit the sponge thickness. A second option is to raise the net height. Either would probally help the defensive players. Personally I would prefer the first option, as the second would require more expensive equipment to be replaced, and should only be considered after careful and complete testing is done.
