True, nothing's locked in stone, but I can't imagine why they would need 7 hotels if it's just 2 parks... I agree that we won't see a 3rd gate for a while, but really, Comcast has shown they can get a lot done in a short amount of time, so I'd imagine they could easily get the two current parks up to speed. The problem is like you mentioned - getting USF and IOA to the attendance levels necessary for a 3rd gate (I'd say both would have to be where DHS, AK, and Epcot currently are - 10 to 11 million). Two full-week resorts is cutting it close - but like others have said, you can easily do USF and IOA in less than a day each. Throw in a 3rd gate and water park - most would probably stay 3 or 4 days. There'd still be room for Disney - just not the 5 to 7 day ones they currently get from most guests. MK and Epcot will do fine since they're already full day parks.
DHS and AK are the two I'd reckon is what's in Comcast's sights. Pandora will get AK to maybe 11.5-12 million. DHS has no additions for the next 5 years at least... and Spirit at WDWMagic was hinting that TDO isn't sure about Star Wars since it's too "boy centric"
so we may not get anything Star Wars until the 50th at WDW.
Potter has grown the market exponentially - and other IPs like LOTR and Nintendo could expand the market even more. Once people start realizing that Universal has something new and exciting every year, vacations may shift - especially when you consider how much WDW wasted on MM+. Not over night, not next year, not even 2016, but by Pandora, Disney's going to find out far too late that Universal is sneaking into the big boys club. Really, over 10 million each and 3 to 4 million for the water park/theme park hybrid would be enough for Comcast to begin considering a 3rd gate... maybe 11 million just to be safe, but by then, the parks would definitely generate enough revenue where a 3rd gate would be to Comcast's benefit.
And it's true that Disney is the only theme park company with more than 2 true theme parks - so I definitely would want Universal to be careful about not taking on too much. But if LOTR doesn't work out, a 3rd gate is really the only thing I could see combating Star Wars Land in terms of hype/momentum.