No, I think the manga hasn't gone too far. There is still much to be resolved. The only problems I have with it are, yes, there are quite a few characters and he doesn't do enough with them, despite them being pretty well developed, and that damned cop out he did at one point in the manga.
That being said though, I love it. Not the American one though, that one can go die in a fire.
And to everyone:
[HEADING=1]One Piece has been going on for 12 years and is still going.[/HEADING]
Just a bit of trivia for you there.
EDIT: I forgot it's cool to hate on this series actually, maybe I'm wasting energy.