Originally posted by: AssertnFailure
how come japanese writers can never come up with good stories on their own relying completely on the manga?

They need to sit down and watch some batman animated series or something, to learn how to create a decent 20 minute plot
The writers have a lot of limitations.

1) Time. They can only do a short story which cannot drift too far from the manga
2) Story. No characters can evolve or die or (insert something important)
3) Continuation. The story must link back to the story of the manga and not cause any confusion

In short, they have to come up with something that isn't boring, and cannot put in anything that will affect the characters and the storyline. Not that easy to do.....