Never say never, but when I think how much they removed WDW from the adult-nightlife business, the odds of a casino seem slim.
I mean, I know various resorts have bars, at least pool bars. Others have lounges with some light entertainment like a piano player. Coronado has the nightclub because they cater (though not exclusively) to a convention crowd. But since Pleasure Island's closing, it seems like Disney doesn't want to deal with the headaches that come with childless adults who want to go park commando all day and then drink and party all night. And while casinos are a license to print money (usually coughcoughtrumpcoughcough), and casinos at least pay some lip service of being family-friendly...they're not all that family friendly really. They have things for families to do, but that usually winds up being things for kids to do while parents drink and gamble.
So does Disney try to create a casino that somehow fits their brand? Or do they try to alter or even forgo their brand in order to make money by operating a casino. Because they're kind of an in-for-a-penny-in-for-a-pound deal, once you shift energy into the casino business, it'll either be so profitable that little else matters, OR it somehow doesn't work and you invest all your energies into fixing it.
Maybe what I could imagine is yet another of Disney's "private clubs" that's essentially run like an upscale 60s era casino, but you have to have big bucks to be a member in the first place so there would be no "I gambled my family fortune away at Disney World" tales of woe (Perhaps with even a maximum amount a person is able to gamble in a night), there would be a dress and conduct code to keep the "VEGAS BABY" bruhs out of the picture. And it wouldn't be big. Heck, maybe they'd change Top of the World Lounge to accommodate this business (maybe DVC could run it and the proceeds would go to reimbursing maintenance fees haha), something with a nice view and feels somewhat elegant, but not intrusive into the ol' "Disney magic."
And of course, they'd have to install Plexiglass around the entire outdoor viewing area, so if someone loses a lot of money, they don't try to jump.