A pity is USJ first, form the first announcements it seem Orlando was going to be the first, this makes it a little harder to visit and I hope is not far from 2020 for the rest of the parks too (although Universal works fast as hell). Super hard to find sometimes good info about japan parks, even if they are great, the professionals that visit this parks are usually doing it in the US, and then the make world tours once in a while, so you have less info about them.
Also the area they chose is a little smaller than Wizarding world, thats possibly one of the biggest areas in the park, and a similar bufget, although 50 millions less is 1 less ride in this terms, and is not like wizarding world has a lot of those, or less detail in theming, that becuase we dont have any details or concept arts is super difficult to predict. Wll they go the modern city "videogames" way (could be as it was a hollywood zone), will the go the disneyland/wizarding world route of a lot of theming done around the games themselves (super hard if they try to do a smash world were they touch different games), or will they try to copy the mediocre cake layout of Nintendo Land with a central theming (the only good idea getting from there is Monita, and I hope they stay the fuck out of anything resembling that game, giant present ribbons and cake theming).
Did some map visualizations to see what the area is getting:
The red zone is Nintendo zone, while the blue lined one is Wizarding world, so you can see they are somewaht similar in size. But then the red thing they did is pretty strange, as it takes part of buildings of 2 other rides, a 4d cinema with sesame street and shrek movies, and a mack coaster themed around space (and totally out of place with the hollywood theming of the zone).
Been reading about those rides and could totally be axed and nobody would really cry. The 4D cinema is pretty bad, it will have nearly 20 years when the Nintendo zone is built, and contains two movies, one of them being sesame street and theres already a zone covering that.
The problem comes with its facade (see image below), even if the red part they draw the whole real building (where the ride really is) is part of the Nintendo Zone, the facade is not, and it can not ve, as thats just the final corner of their Main Street, that clearly are not going to touch.
But, MAYBE, what they do, is let the false cinema facade intact (taking away the sesame and shrek logos of course) but closing it to the public and leaving it just as theming of hollywood main street, while the real building behind it is used by the Nintendo zone. At the same time left of that corner is actually, if they dont close it down and make the entrance elsewhere, the entrance of the Nintendo zone (thats why I said they could use a "modern" design for the general theming of the zone, so it doesnt clash with Hollywood main street), but who knows.
Then theres the Space Fantasy ride, a mack spinning coaster trying to do something similar to Space Mountain, with a pretty bad story, totally out of place with the hollywood theming (the entrance looks more like a nasa building), going to mark its 10th year when Nintendo zone opens, and IMO totally "disposable". Again the problem is, the red zone only takes away a small part of the building where the coaster is. This could mean the ride stays completly as it is and is the end of the Nintendo Zone.
But it also could mean something interesting, and makes sense with the budget they said. They could actually use it FOR the Nintendo zone. Starfox ride? Super easy to let the coaster layout and change the theming to it. Metroid ride? more of the same, even F-Zero. The problem, all this space franchises (except starfox right now but who knows in 2020) are not really that popular, and much less in Japan (although I think they wil actually use the same mld as the did with wizarding world in other their other parks, so they porbably thinking about world wide Nintendo, and not what is popular in each country, at least for the big rides and central theming), so again, anything could happen.
And then theres a very slim chance to see a big coaster, becuase theres alredy one passing inside the Nintendo zone (just near the entrance), the Hollywood dream ride. So if you guys are waiting for a similar coaster themed to Big Blue or Mute City, dont get your hopes up. I do not even know how (or if they) are going to try to cover the coaster form the rest of the Nintendo zone so it isnt out of place.
I think that covers the majority of things that could happen, but of course, we need concept art and info about what is going to be closed left open to know exactly what they want to do.