To me, the Fast and the Furious roller coaster is a hands-down winner of an idea.
People will love this, both the look of the ride on the hillside and the interaction with the existing park elements (i.e. Escalatorland).
It sounds very similar to me to Velocicoaster, which sounded similarly lame and unthemed when it was announced and being built, but the way they did it and the way it interacted with existing park elements (and the queue is fairly well themed), combined with the quality of the ride, made it one of my favorite things Universal Orlando has ever done.
That's what I'm envisioning here, and there's no reason they can't use the template of Velocicoaster and the topography to make something interesting. It's no mystery why they're doing this. Why shouldn't they exploit their geography and setting to do something that couldn't be replicated anywhere else?
It also adds more ride capacity, which they need, without removing much else (although it does seem like it might be replacing the Special Effects theater, the Animal Actors theater or both. THAT to me would be a bummer, but hardly something that would be impossible to rebuild elsewhere).
I could see why they would want a roller coaster that wasn't either for children or wasn't widely known as an inferior version of a coaster in Florida. One of the things that makes USH a hard sell for many used to Orlando is that there's almost nothing that's unique to people used to UO. Rightly or wrongly, USH acquired a reputation as being a park where you had no reason to visit if you had done Orlando, with the Studio Tour really being the only counter to that. This, SLOP, and (temporarily) Super Nintendo World will give those people a reason to care about USH.
And given that no one likes the Fast & the Furious Studio Tour scene, this will likely ensure that FATF will no longer be part of that attraction.
From where I'm sitting, almost everyone wins here.