I've actually had this thought in the past. I've thought put my mind to so many different things that could replace Hollywoodland and I can't think of anything that would seem to be a good land for that area except for The Simpsons. A smaller version of Pandora I could also see happening, but The Simpsons provides them so many opportunities in retail, food & beverage, meet & greet opportunities, and ride potential.
I don't know how popular The Simpsons is in France, so I don't know if it'll happen at WDSP, but I can definitely see it happening at DCA after the contract is up at USH. Something will have to replace Star Wars though because that lagoon is going to feel pretty empty with the only thing currently being built around the lagoon being Frozen with a bunch of expansion pads around it.