Why do u think they have not yet made a good fantastic 4 film? Both versions are average. Is it difficult to adapt?

A good question. I have not seen the "newest" one I guess. I saw the other two, and while I liked them; I felt that they were incredibly slow. Like, it took a conscious effort to stay vested in the film. I have not had this problem with any other of the Marvel films. I'm guessing this might have improved with more attention focused on the script and the director.