Arguments against monocropping are pointless unless you're dealing with geographic regions. Changing my farm from corn to soybeans doesn't mean jack if the guy next to me is rotating corn and soybeans as well, and the same is true of his neighbors and so on.
Unless you're able to coordinate and schedule the growing/raising at a county or state level you arent going to have impact on mutation or spread of disease. You may actually cause more harm than good by forcing ecosystems in a large area to adapt rapidly, raising the possibility of severe unintended consequences.