What can I say, I'm full of some amazing ideas.
Yeah, it would have to be done right. I've been to a few indoor parks now, and they just look & feel like shopping centres/malls. It would have to be spot on inside and out, perhaps with Flight of passage, a flat ride or two, and maybe a more original ride. I don't think the River Journey would be a good fit, as I would ideally see the inside of the land being themed to that standard, plus with Frozen it would be too similar. Perhaps a coaster similar to Tron?
I would want it to be amazing though, I love what Disney did with the Disneyland park, there are so many elements to it that are superior to the US parks, but that does not cross over into Studios at all.