Coming from Michigan, I agree that many people from Michigan go to Traverse City, Mackinac Island, etc. (they call it "up north" here). It is as crowded there in the summer as it is in SoWal in the summer. The cars going from Ann Arbor to "up north" in the summer beginning with Memorial Day is a crawl for hours. I've only been "up north" a few times and thought it was very nice, though people who go up there regularly say it is awesome.
If the midwest becomes a prime target for people who want to go to the Panhandle, then this increase in demand will come from several sources (and the midwest is just one of many potential markets):
1. People from the midwest will be people who want to buy a second home to use in the fall, winter, and spring and then rent it out to people from the south in the summer. (like me)
2. Retirees from the midwest who want warmer weather in the winter but who see SoWal as affordable compared to other parts of Florida (and who like the year-round weather -- e.g., avoiding the extreme heat in the summer).
3. Retirees and others who like the natural environment and a "casual" upscale and active lifestyle.
4. Renters from the midwest who can travel in the shoulder months (retirees, singles, married no children, married young children) and who want nice places to rent for off-season vacations.
Word-of-mouth will probably be central to drawing people from the midwest to SoWal. That's how we heard of the area. Once we came here, we loved it and now we tell people. As someone who lives in Michigan, I can say that there is very little advertising for the Panhandle areas for vacations/retirees at this time in our area.
Of course, I'm sure that not everyone wants to see an increase in demand for the area.