Silly Swirly can get wait times up to half an hour, though I don't think I've seen it higher than that. Truthfully, a 30 minute wait for a spinner is pretty long.
I just don't really care for an IP like Potter to get an attraction in the form of a spinner. Just doesn't suit it in my opinion. Jurassic Park, on the other hand, is different because it just so happens to be a cross between a prehistoric zoo and an amusement park.
Quite honestly, I would prefer something in this mystery spot that wasn't an attraction. A themed locker station, a sit-down area (larger than the Owlery in Hogsmeade), another spot for snacks/drinks, all of the above - all fine by me!