I haven't read anything to suggest that a movie is on it's way out, but you got to think is a movie the best thing for the series or does it take something away?
If there is a movie I hope it will resolve what ultimately happens to the Seed ship people and Knives. I hope for Knives to be redeemed but his life history isn't promising at all...
I also hope that Vash and Meryl get married and Millie finds someone to love her the way she loved Wolfwood.