*sigh*
Whatever happened to the park that was making major, high quality additions year on year?
Tussaud's grew the park to the point where adding more flat rides wouldn't grow the park further. The big expansion in the early 2000s changed the park from the family water attractions to the heavy thrill ride park. Once that placemaking was done there is less need to invest every time.
Thorpe has realised recently that just focusing on high thrills doesn't always bring in the right sort of guest, hence trying to go for a wider range of attractions recently.
Also as Rob said, IPs make good headline attractions. Most other parks are doing similar things, Universal went for Harry Potter, Disney are converting a ride about Norway into a ride based on thr film Frozen. Original concepts seem to be dying out. Which is a big shame I think, the best rides at Disney are original ideas (Pirates, Jungle Cruise, Tower of Terror).
Overall though this could be a good little addition. Or it could go the same was as Saw Alive and only last one season!
Done well like the Dungeons with the right leg tickler type effects (think of the Sweeney Todd scene at London Dungeon) and stuff it could work really well. But for a good experience, the throughput will be tiny like 300 per hour (25 people every 5 minutes). Too many people and not everyone has a good experience. But too few through and the queue is huge.
Personally, it doesn't make me want to go to Thorpe Park though. But then I don't go for Fright Nights either.