I wouldn't entirely discount the possibility of Disney allowing the release of replica walkarounds, especially based on vintage costumes. They've already allowed the release of replica vintage mouseketeer ears (like Annette Funicello wore), and have allowed the release and creation of vintage monorail replicas (miniature, of course). That's not such an outlandish idea.
For me, having replicas doesn't diminish the impact of the property. I own a lot of props, stuff from Star Wars, Lord of the Rings, Pirates of the Caribbean, Harry Potter and about a dozen other movies. I have costume replicas from Lord of the Rings, displayed on mannequins, and I have life size Mogwai replicas from Gremlins and Gremlins 2. Seeing all of this makes be better appreciate the painstaking effort people go to, to make movies and fantasy real, and it has never diminished my appreciation for the real thing. I've attended many Star Wars prop/costume/etc exhibits, as well as the Lord of the Rings Trilogy Exhibition, and every time I see items at these exhibits, I'm still moved, I'm still awe struck, and I still feel just like a kid the first time I saw Star Wars (obviously I couldn't have also been a kid during LOTR though).
I have a life size Legolas costume on a mannequin at home, but remember the feeling I got seeing the screen used Legolas costume at Lord of the Rings exhibit. Seeing what went into just creating a replica helped me appreciate even more all of the painstaking efforts that the crew went to, to make the real thing.
I can look at my lifesize Gizmo sitting on my shelf, but I still have the same emotional response when I watch Gremlins.
I collect replicas because it supports my appreciation and affection for a given license. Seeing the real thing is still moving. If anything, owning a Kermit replica will only increase my desire to take a pilgrimage to the Smithsonian to see the real thing.