If the gettable names being bandied about in this thread are the only ones out there then realistically, the value of changing the current coach is hardly going to be worthwhile.
Clarko and Simmo make sense if they were attainable. Mitchell as well, and as much as it pains me, Hodges has more leadership skills that he could teach than any other of the possible candidates. I'm not convinced that any of those blokes are likely to take on the job though, even if the stars lined up regarding contracts and so on.
Even Ratten would probably prefer to have a chance to finish the job at the Aunts, as that seems to be working out.
Sumich... He seems to be respected as a developer, and North have plenty of room for that in order to improve. But other than what I read here, I know nothing.
But the suggestions of Leppa, Voss and their Ilk. Na. Please, just no.