Part of the problem is the character isn't exactly copyrighted. It is the reason why we just had a recent lawsuit about Sherlock Holmes. You are free to create a book or movie about Sherlock Holmes. Just don't use any of the info from the last few books in the series. I think that Disney should be able to protect Mickey in a trademarked way, and do it at a cost. But it is going to be more complicated than "you can't use the characters"