You want to start theory crafting a new theme park? I'm willing to bet a few glasses of scotch between the two of us, we could come up with a few ideas that could at least start the conversation before logistics and cost come in to play. There are plenty of ideas out there already since this isn't a new topic. The most popular one is a Villain park. Imagine a mirror image of MK but it's all Villains. I'm not the expert here though.
There are always risks to any major project of that magnitude. Labor, logistics, land, space, cost etc. I'm handwaving those issues away and just discussing what if Disney built a brand new theme park in florida, and it was great, how would it impact the market and visitor vacation habits and routines.
Regarding AK, I'm not saying it's a bad park, and I think it's wonderfully themed. But look at the gate numbers compared to MK. Let's compare the numbers of HS once SWGE opens and it's been operating for a full year. AK with one of the most popular rides on property still can't gain traction over Epcot or HS. Everyone has their favorites, but that's anecdotal.
HS is a mess. It will be a mess for a long time. I really love the direction their going, but until they actually add additional lands like Cars, Jones, Monsters, Incredibles to balance out SWGE, it'll still be a confusion of different themes and different directions the park has gone through throughout it's life. To be fully realized they need to somehow remove a lot of the "Hollywood" theming outside the entrance to the Chinese Theater area. The park is just a giant pile of bandaids, but SWGE and TSL are gigantic, monumental steps in the right direction. The non-land areas are going to need some better themeing and facing down the road.