I don't think they'd last long if they did gain power. I could imagine them coming to power as a bit of a mistake and just going mental with their platforms, at which point a lot of their supporters would find out about the negatives of ON. I think tourism would decline as Qld would be seen as a bit Jackboot by the rest of us, and I think all other state and federal govts would gang up on Qld.
A couple of by-elections, may see them lose govt before the next election, and the rednecks may be suitably chastened.
Yes, I think that if they ever did gain power they would fairly quickly have to moderate their stances (losing their 'maverick' status, which was their main drawcard to their supporters), or else risk massive backlash from non-ON Queenslanders.
Also, I strongly agree with the idea that the rest of the state and fed govts would gang up on the ON government. It reminds me a little bit of the EU's stance towards Austria's far-right led coalition govt headed by Jorg Hader a few years back. The EU imposed mild but symbolic sanctions of a sort against Austria for this.
Of course the situation is quite different in Australia, as all the states form a single nation-state so any major 'sanctions' against Qld would be impossible and unconstitutional. However I can see their being a snubbing of the ON govt ie Qld premier conspicuously not invited to events where all other premiers attend, etc (more symbolic thatn substantive). Also, in regards to special purpose Fed grants to the states what is the constitutional status of this, ie as they're discretionary, would the Federal govt be able to withhold these from Qld. If so I can see a situation where regular Federal grants continue (for basic funding of schools, etc), but where particular grants (ie pork-barrel) spending is stopped or severely reduced.