Agreed, the Muppets are a collection of characters with various personalities. Stitch is one creating with only one characteristic begin used (his obnoxious one too). It would be much harder to tire of them, especially when they have a broader range of emotions to display (even more than the precious "fab five").
That begin siad, they could still screw it up by doing something like putting out way to much of that unfunny Pepe freak whom Jim Henson had nothing to do with.
Marni, for once I hope you've heard wrong and that there could be work done with them at WDW. Even if only for promotional reasons Disney should take advantage of the property they fought forever to get. Using them to promote thier newest film would also be a smart thing to do.