Could we form a new state of registry which would actually adhere to ICAO, with our own registration prefix. Adhere to maintenance schedule as set out per the manufacturer, and have a sensible "minor modification" system, along with adhering to STCs set out in FAAland... Make it a worldwide thing (as ICAO aimed to do).
Without all the bureaucracy and money wasted on paperwork...
(And no I don't mean something sensible like the "permit to fly" I mean something that is accepted worldwide)
Anyway, silly ideas aside, some country specific differences are good to have, for instance in NZ the low flying (due wx) and the terrain awareness (to avoid mountains). It's also quite useful to have local differences training.