Would love to see Luna Park Melbourne do what Luna Park Sydney is currently doing, bringing the park back to its heritage roots. I honestly think the current space has a lot of potential, but at the moment, the only thing going for Luna Park is it's historical value. It's in a bit of a weird state, where you have some great classic attractions like the Scenic Railway, Ghost Train, Carousel, etc. but then right across the road is some Meisho swinging ship piece of junk...
I think just a revamp of exisiting rides would do wonders, actually making them fit within the boundaries of a 'classic amusement park' instead of just having random bits of theming strewn everywhere. This could be done whilst adding in a couple of newer attractions that would capture the attention of punters, but still fit in with the heritage feel of the park. A coaster I feel would do wonders here, something like a compact Eurofighter, but I think even classic attractions such as a Wave Swinger and maybe a well themed Air Race would really liven the place up.
And for love of God, keep the damn Enterprise...