Provided this film doesn't simply rot in the bowels of development hell, even if it does well, it's not going to be like the anime which inspired it. It'll probably end up looking like more Firefly or something similar.
Why? For the simple fact that NO live-action movie can accurately replicate an anime, regardless of who's making it or what country it comes from. Not even live-action Japanese films can replicate anime. Anime is by its' very nature, a cartoony visual style. Elements such as Spike Spiegel's fluid movements or the very character of Ed (a gangly monkey-like girl who can type on a computer keyboard with her toes) simply can't be reproduced in live-action. So regardless of how well a Cowboy Bebop does (for all we know, it could break box office recorRAB, though I honestly don't see that happening), at its' very best, it will only reserable what it is: a Hollywood movie inspired by a Japanese cartoon.