I get what you are saying, but I feel like that speaks to my overall point that the IP is so popular people will continue to travel for it even if their park is incredible. If you build another Hogsmeade with a great ride that isn't Forbidden Journey or Hagrid's, are you really going to spend thousands of dollars to come see Hogsmeade again in Orlando? Will it be different enough to warrant spending a week in Orlando and multiple visits to the Universal parks?
I don't think you will handicap your new park at all because the competition of true theme parks with large, well known IPs is very slim in the UK and surrounding areas. The rumored IPs of Lord of the Rings, 007, Paddington, Back to the Future, Jurassic World, are all large enough for people not to be overly upset that Harry Potter isn't there to the point they don't show up.