I still see it happening at IOA and USF, I just don't see it happening with it strictly the right side of Islands and the left side of the Studios. I think they'd have to live with the deadzones, and utilize more of each park than that. Maybe not to their fullness, but at least more than that. If they did that, there's the possibility of keeping the Mummy, Simpsons, MIB, Cat and the Hat, Spiderman, and Jurassic Park open at least. This is excluding Forbidden Journey because we don't know Rowling's stance on that, and also Hulk, Rockit, and Dragons Challenge because of the coaster situation. So I take it that agreement is still in place about the noise ordinance then? Anyways, if they spread it out you'd have better space (and with some dead space) to utilize for scares and more rides to keep open for the people who prefer to do that. I still don't think the average guest would care that much about walking back and forth between parks. They do it during the day without complaint (for the most part). They can do it at night.
Also, during the years HHN was also at IOA, did they ever keep the Toon Lagoon rides open? Just curious.