I agree that Hill Valley would make a lot of sense as a Springfield replacement. That being said, I still don't think Twisters would be the best option for a Supercharged successor. If the park wants to bring back older IPs, more marketable properties like Jaws or Ghostbusters would make more sense.
For variety sake, between whatever places Supercharged and Simpsons, it might be an idea to use a classic property for one, and a more modern IP for the other.
That rumor seems to mainly apply to attractions. It's currently speculated that the UK park will have Jurassic World as one of its lands, and it will most certainly have the presence of Minions in some form.