So the big question now is: Why Soundstages 22-25 when we already have the former Soundstage 28 land sitting unused?
Let's get the big question mark out of the way: Nintendo Land? Soundstages 22-25 take up about 100,000 square feet - including the road between 22/23 and Soundstage 28 - which is not much over 2 acres. Adding in the Soundstage 28 space only gets it to about 135,000sf, one extra acre. Nintendo Land is going to be north of 200,000sf. Adding in Soundstage 29 and 31 gets the total closer to 200,000. That's a really weird shape but it's not unworkable. 28 could be the main courtyard with a ride building going into 29/31 and one or two going into 22-25. But Nintendo Land isn't scheduled until 2021 for USH, so this is at least a year early. Considering nothing's going on in Japan - which gets the first version in 2020 - this demolition isn't for that.
The other big question for some would be Diagon Alley, but I just can't figure out a way for this to work down here. (And I actually found a way to make it work in the WaterWorld space.) The ride building is about 100,000sf and Diagon Alley itself is another 90,000-100,000sf (not counting Kings Cross but counting some portion of the London Waterfront) and both spaces are pretty wide. The ride building would need small portions of the Panda Express and Jurassic Cafe buildings, but then Diagon Alley would need all of Soundstages 28, 29, 31 AND Transformers. So, I'm going with no.
So what else? I think everyone is in general agreement that the Lower Lot is a mess. It needs a central plaza like nobody's bidness. Soundstage 28 is obviously not central to anything, even with the addition of the 22-25 land. The obvious placement for a plaza would be the Panda Express building. But where would they move the stuff in that building? They could move it to Soundstage 28, but they could've already done that. Demolishing Soundstages 22-25 DOES open up an area for the Jurassic Cafe building to expand. But there really isn't all that much in that central building for it to take up 100,000sf.
Obviously they can do a mini-expansion of Jurassic Park. I'm sure a nice Raptor Encounter is on the menu - it can actually be advertised as an attraction without annoying too many people. And they could make the kiddie area less pathetic without taking up too much extra space. It doesn't need to be Camp Jurassic, but enough to turn it into an actual attraction itself, something along the lines of one of the Super Silly Fun Land play areas. But these aren't exactly earth-shattering ideas. The Studio Tour has long been rumored to be moving back down here, so I checked and the current island that attraction occupies takes up a mere 53,000sf (ish). I originally thought they'd put it where Soundstage 28 was, but 22-25 is actually the BEST location for it. Kirk Douglas Dr, the road where the trams currently load/unload, wraps around Springfield, goes under the Starway, and then down to the backlot where it turns into the road that sits between Soundstages 16-20 and 22-25, which gives the trams separate unload and load areas without taking up any valuable theme park space. Take away the escalators and the buildings around them and the entire queue area takes up less than 35,000sf of space. Which allows 65,000sf of space for Jurassic Park extensions, a gift shop and whatever they need to transfer out of the Panda Express building. (I'm not moving the tram garage here. That can go anywhere.)
What I'd like to see is better immersion down here. Enough with the soundstage-chic! How about you enter the Jurassic Park gate and you are actually in a land filled with trees? A land where you can't see The Mummy RIGHT THERE? How about entering a Mummy-based land by entering through an Egyptian-style arch and the ride building is an Egyptian temple and you are surrounded by palm trees and equipment? I have no clue what kind of environment the Transformers would be in, but part of one of them took place in a desert - I have only been about 90% successful in removing my one Transformers movie experience from my memory, OMG, I just remembered I actually saw the second one also - so maybe link these into one themed desert area? Create little areas for photo ops and for kids to fool around. Move everything that ruins the theming into the new plaza or the Studio Tour building. Make that building two floors and give it a nice seating area up on top. You're welcome!