I have looked at this, but as the old adage goes, what goes up, must come down. The incline in the other direction would be from billabong, via tiger island, back to central station. As I undersand it, the grade is gentler than the new proposed route, but steeper than that of the Blue Lagoon loop.
I'm no train buff, so i'm not sure whether it would work or not. I'm really hoping that they have actually brought in some rail professionals to advise them on the re-routing, that they've done the math on the grades involved so that they can continue to run the train. It'd be a significant loss to the park's kinetic energy if they go to all this trouble and find the train can't make it up.
I guess we'll just have to wait and see.