@VampireWicked
I agree with what you mean but I was more interested in how to handle making bigger changes to the overall story of the Franchise rather than dialogue. Dialogue is important but its something that would change in any adaptation regardless of meduim or country of origin.
I was thinking more along on the lines of Durara!!!! because I wanted to create a new lead(s) to focus the movie on rather than try and cram the season into two hours so I want to bring in the writer to help keep the style intact.
Same thing with Cowboy bebop, rather than extend a case for an hour and a half or go through half a season in 2 hours I rather just create a new case for the Bebop crew to deal with.