They still have Kidzone to do. They need to upgrade (and hopefully not replace) E.T. as well. They can knock down Twister any time they feel like it. Potter will draw people in for a few years on name alone. I understand needing to space everything out to give people a reason to come back, and to make sure attractions are really good rather than doing too many of them and some being of poor quality in the end. I'm also impatient.
But if they were going to upgrade T2 after Hollywood's version closed, it's been a few months. If they're ready to go refurb it, let them do it.