I live in Australia, and while I am not a fan of Apple or their products,I have to say that I'm surprised anyone in their right mind would go bush with just one map. Electronic or paper, maps have errors. Don't bet your life otherwise.
Mildura isn't really going bush, depending on where you're coming from. I'd (before this article) be pretty comfortable following phone directions from say Bendigo to Mildura, which should just be a straight run down Calder Hwy. It seems pretty reasonable to use it to find a route between two cities/towns, which I've done in WA a few times with Google Maps.
Though I'll admit I've never used turn by turn for that, rather just got the broad strokes. Is this a problem with turn by turn directions, or is Mildura actually in the wrong place on ios6 maps?
EDIT: Took a look, seems like Mildura is actually marked at the wrong location, which is significantly worse imo.