I'd say the question comes down to this:
We have identified a tendency of at least one foreign airline is to select an idle thrust descent mode to minima when conducting an NPA. That is downright dangerous.
Since we as a county do not want an airliner splattered on the ground, we have two choices - either restrict those airlines' operations to Australia until they can demonstrate suitable training for NPAs, or install ILS approaches on all runways those airlines will utilise.
For the relatively small cost of 1 ILS installation compared to banning airlines, I would go for the ILS.