I'm all for a fully realized Potter-level JW in Gate 3. IOA's JP is kind of lame, IMO. An outdated exhibit space, a whole lot of generic carnival games, and a single decent water ride. But if the Gyrosphere attraction is half of what's rumored, I wouldn't care about JPRA leaving too much anyway.
What I could see happening is a Great Hall dining spot right behind Hogwarts, but everything else becoming an extension of Skull Island. "The Lost World" or "Monster Island" being possible themes, bringing in IPs like Godzilla or Pacific Rim.