Okay after a discussion on twitter with Theme Park Insider, I'm going to do some spitballing. The following is based on absolutely no inside information and is highly, highly speculative.
IF this is Transformers, I actually could see this marking the beginning for the end of MSHI. I know I've always been one of those saying that Marvel won't leave Uni any time soon, but this whole project just brings up so many questions. First of all, the rush. They obviously want this done sooner rather than later, and the project seems to be a surprise to everyone. usually you'll have one or two people knowing before this happens. But everyone seems to be scrambling to get everything into place here. Why? Is it because they know they might be shutting down Spider-man for good a few years down the line?
Then we factor in most people's insistence that Transformers wouldn't be coming to UOR in the past months. What changed their minds? Now, again, the following is a huge leap and assumes quite a bit, but here we go. What if Disney offered them something they couldn't refuse? And what if, with that knowledge, they inquired with Warner Brothers (who they already have a great working relationship with considering WWoHP) and got the Floridian rights for DC Comics, who are owned by WB. Now, Universal has a pile of money from Disney to retheme the land to DC after Potter Phase II opens as well as add a new ride to the area, and also has Transformers to lighten the load while Spider-man is rethemed. I don't know if it's possible, but its intriguing.
If I get Transformers, Batman, Potter, and an Avengers ride/land for DHS out of the deal I'm all for it.