Watch the mariachi trilogy and think about what a good interpretation of bebop could have looked like.
Take the trope of ridiculous large swords that supposedly are just made of metal, and are heavy, but somehow the thin and slender wielder can swing about with ease for hours on end because 'they trained for it'. There is no scenario where you could adapt that to live action without it either being completely ridiculous or modified to an extent that the existing fanbase will hate it.
This is the problem with many plotholes and plot devices that are used inside non-live-action and non-scifi media where it simply breaks as soon as it is taken into live-action. Some of it stems from the never-ending use of serial/procedural series where the main characters need to remain the same for a long duration (and as such no real damage or change can be made), while other issues are mainly due to the huge gap between reality and unexplained differences.
Just a few movies that do this well that come to mind:
* Scott Pilgrim vs the World.
* Kick Ass.
* Ella Enchanted.
* Amelie.
* Thor: Ragnarok.
* Space Jam
* The Mask
They were trying to pull off Robert Rodriguez without actually having to pay Robert Rodriguez when they would've been better off paying Robert Rodriguez to Robert Rodriguez.
Instead all we got were a bunch of Dutch angles.
I was surprised and impressed with just how well they managed to mimic the vibe despite being live action, but I guess everyone experiences these things differently.
The live action version also doesn’t have the sense of ennui and has fewer quiet moments to just let things exist and breathe.
It is hard. For example I'm not exactly Tarantino fan, but I recognize his stylistic approach and find it good. If someone would like to copy Tarantino they could easily arrive at a mediocre straight to DVD B movie. The difference is hard to describe. I feel it was the same with Cowboy Bebop.
This I don't agree with, not that Vicious is or isn't thinly written, but that it is valuable or an improvement that he is "fleshed out". Spike's narrative in the source is built on his memories and recollection of people, not who they are. The lack of dimensionality has a purpose. Jet has a similar issue and both of them are forced to confront the gap between their recollection of people and what those people actually thought/felt, and that's big because both of them have staked major parts of their personhood on the ghost of their nostalgia and self-centered sense of tragedy. Finding out the world is other people doing other things was the point and you can't recover the impact by removing the entire mystery.
As I said elsewhere, Bebop is more related to 70s New Hollywood than the American adaptation is, Coppola's The Conversation has a similar bent where someone is haunted by their past but misinterprets the present and future on behalf of their own guilt only to discover reality had nothing to do with a POV that was always their own misperception. If you actually followed all the side characters around the movie would be pointless.
Visually, I think the show is amazing too.