If you're an international coming to Australia for a few months, mostly climbing, wouldn't you expect a 3star route at one crag to be of similar quality to another?
Those who plan to use the guidebook repeatedly can take the time to learn the system and it's idiosyncrasies; but if your market is truly the occasional visitor - then you need to consider what the bar is set at by other guidebooks.
Do current authors who regularly contribute want to offer up some % stats as to how many sales they've made in Aus;online OS etc?