Looking at Merlin right now, it would be very strange seeing them invest millions in a dark ride that wouldn't be as good as anything in Orlando. Merlin also doesn't have the size or money to build and maintain something that big.
I would want to see one in the future but I think it's very unlikely.
Well they did in Ghost Train not 2 years ago, and personally this holds up to a good deal of Orlando attractions. Not to mention investing in Heide Parks’s Ghostbusters which uses a very
similar ride system to Spider-Man only last year. Never say never.