I heard there was a plan that ALL AN's must lead in NSW, but as soon as they reach the SA border they must be reversed. No AN is allowed to lead in SA on the grounds that it excites the local population too much.
That's a valid concern - think of the danger of wheelslip from the foam!
On a more serious note, they're a modern (comparatively), high horsepower locomotive. I would think (as a layman) they would be well suited to the heavier trains in NSW on the grades, like the ore trains, Manildra trains, garbage train etc. If I lived in SA and wanted to see AN class, I'd rather travel to NSW and see them working in multiple leading trains, than as trailing units on the odd intermodal train...
But that's just me, being rational and all!