Ways to make this movie not fail:
1. Keep the sweet jazz music, wouldn't be bebop without it
2. Dont go over the top with the Outer Space aspect of the series, the best parts of it are the parts that feel like they could be taking place in modern day, like the Spike vs. Vicious fights
3. Have Vicious be the main antagonist.
On that note, i'm pretty excited about a cowboy bebop movie, its the series that got me into anime back in the day.
edit: @ ura, theres enough of a story with spike for a linear plot