So currently it seems that the only mob affected by EMP towers is the creeper (and many modded derivatives), in that they become charged when near one as it goes off. It would be nice to have more control over what the EMP tower can do to other mobs. Ideally this would be a crafttweaker event that would trigger every time a tower is activated, and would return a list of entities within the blast range. If this were added, it would also be nice to have an option to disable the current creeper charging mechanic, so packmakers could totally customize how every mob is affected, including creepers.