I reckon that this will appear in the Towers, perhaps with the drop track tech repurposed in a building extension outside the perimiter of the building, ala Hex. Well, presuming they can ensure you board at the bottom and head up then down, rather than the reverse method introduced on N:ST?
Not keen, though, I have to say. I know Merlin are all about cross-brand pollination or whatever, but there's a Dungeon at Warwick, another in Blackpool, York, London... All easily within reach of Alton's central customer base. It's not like a Madame Tussauds existing in New York, then another in Shanghai.