While I don't disagree that a tower may be warranted at Ballina, the cost of operating there will increase. Secondly the access to the airport will be curbed significantly, especially in the case of IFR training, I assume RPT flights would be given priority meaning private and training flights will be restricted in what they can do around those arrival times. One thing that class D does not do is increase efficiency of the airspace, especially non radar, so do not expect an increase in traffic handling as a result, most likely the opposite.