Hmm... I didn't get a chance to ride the Scenic Railway due to it being in annual maintenance on the days I was in Melbourne earlier this year...
Though, I agree they need to step forward. I too would love it if they replaced that stock-standard steel portable with a proper woodie. Also, I did think that there wasn't a lot to do there, I think we only spent a few hours in the park. Also I would'nt know about the food either, as we went to one of the places on Akland St.
As for Sydney, I think if they installed a dark-ride type coaster it would be alright, just make sure that the walls have some sort of sound-proofing in them.