I actually think it looks great. The themeing looks incredible, and I think Merlin can definitely pull it off.
Okay, the 'ride' part looks short, but, I reckon it will be fast, have some nice pops of airtime, and the fact is stays low to the ground and through the trees will make it even better.
I think the building part will also be good. Someone mentioned having a show in there. That would be cool, and different from your average coaster. (Except a few out there).
I have no idea about a world's first, but I don't think it really needs it.