It was a combination of legal headaches, and Michael Eisner trying to persuade Jim to throw the Sesame Muppets into the deal.
In regards to the former, Jim did almost all of his business dealings on handshakes and words (as with Lord Lew Grade - there was never a contract or written agreement for doing TMS or the first two Muppet movies, they just shook hands), but with such a big deal with Disney, there were all kinds of lawyers and legal advisors and what have you involved, making everything more and more complicated for Jim, who wasn't used to doing business in this manner. Unfortunately, his traditional business practices came back to bite him after he died: because the deal was never finalized, Disney went ahead and began using Muppet characters and properties for merchandising and theme park attractions and such - JHC said this was copyright infringement because the deal was never finalized; Eisner argued it was okay because he and Jim had a verbal agreement.
As for the latter, Jim said from the get-go the Sesame Muppets would not be included in the deal, but Eisner kept trying to get him to, but he was adament that they wouldn't be included, and grew increasingly frustrated that Eisner kept trying badger him into throwing them in.
In regards to the former, Jim did almost all of his business dealings on handshakes and words (as with Lord Lew Grade - there was never a contract or written agreement for doing TMS or the first two Muppet movies, they just shook hands), but with such a big deal with Disney, there were all kinds of lawyers and legal advisors and what have you involved, making everything more and more complicated for Jim, who wasn't used to doing business in this manner. Unfortunately, his traditional business practices came back to bite him after he died: because the deal was never finalized, Disney went ahead and began using Muppet characters and properties for merchandising and theme park attractions and such - JHC said this was copyright infringement because the deal was never finalized; Eisner argued it was okay because he and Jim had a verbal agreement.
As for the latter, Jim said from the get-go the Sesame Muppets would not be included in the deal, but Eisner kept trying to get him to, but he was adament that they wouldn't be included, and grew increasingly frustrated that Eisner kept trying badger him into throwing them in.