I can't speak for Aussie but for NZ I see RUC as the most fair option, distance travelled is the most accurate way to measure wear and tear coupled with vehicle weight and number of axles/tires on the road and that is exactly how the RUC system works in NZ. I would push to get the excise tax removed from petrol and have all vehicles charged via the RUC system.
There probably does need to be some adjustments because the system was designed for heavy diesel vehicles and basically everything under 3500kg is classed as a light vehicle. I would suggest they need to add a category for vehicles under 2000kg to allow for true passenger vehicles.