There are already problems there. I have heard on more than occasion of the people (one of which was an Air NZ checkin staff memebr) that monitor the MBZ frequency advising (normally foreign pilots) of a rather large Mountain to the north that is going to get in their way very shortly. That is not their job and, it has prevented fatalities.
That mountain got in the way of someone else with tragic consequences recently and, having seen the ATC setup in Hamilton (when i was shown the SSR movements on the ground at AA), a controller watching the flight path of inbound IFR flights with the same equipment would probably have a good chance of preventing that sort of accident again.
I have had to go around (when established in the circuit) before because of muppets not talking on the MBZ (they were trying to find out from Christchurch if the jump planes were dropping when wanting to conduct an IFR approach in VMC conditions instead of monitoring and making standard reporting calls as required!). The Taupo MBZ was and still is a joke. It is a matter of time until the inevitable happens and MOR, sadly I think your last statement has hit the nail on the head.
When it comes down to it, the arguments for Taupo ATC far outway the arguments against so the CAA now need to get the balls to implement it. They also need to get ATC at ardmore! These are two of the busiest and most complicated aerodromes in NZ with all the movements yet ATC is put into other less important places!