IOA changed a lot between 1992 to 1996, but by the time they actually announced details for the second gate things were pretty much how they opened.
They did announce that they were building a new theme park, all the way in 1993, but only vague concept art with no defining characteristics was released. In 1995 more concept art was released as part of a master plan proposal, however, again, no charcters, themes, or even a park name was included. By the time they actually announced IOA and its details, they were actually locked in. All the big changes happened prior without much of the public knowing until years later.
I don't think much would change at this point in the development process for Epic Universe... but man oh man I cannot wait to learn about the changes that happened in the years leading up to now.