It is going to be a movie more or less because Disney realized they were not going to be able to make money from adding streaming content, but a movie might, so the scripts for Season 4 were cannibalized into a movie instead. It's about trying to make money with the IP.
I have always felt the show was aiming for after-school cartoon quality like GIJoe or Transformers, so I am already anticipating the movie to be like those franchises' 80's movie efforts. Not expecting much.