@RoboBlue:
I think a large part of this recent flood of positive attention is disinterest in other anime. From what I've seen of Naruto Shippuden, it hasn't handled the pacing very well (despite an increasingly interesting manga story), and Bleach has outright interrupted the main plot with filler arcs. Despite being slow, One Piece is still detailed enough to hold your attention through almost every episode, which says a lot for an anime this long.
this is definitely part of it; it seems around the time shippuden's portion of naruto started and the series began losing lots of fans, myself included, those fans either picked up bleach or one piece. that trend seems to be continuing with the burgeoning suckness of bleach as well. there are still plenty of fans who just can't give it a chance due to the art.
on top of that, naruto had not only huge internet word of mouth in manga form - thanks to toriyama'sworld's scanslations - before the anime even began. and the naruto manga genuinely had stronger opening arcs than one piece did.
@JERK:
What the hell is this bullshit about Dragonball being looked down on.
dbz constantly got panned by critics, but all the pre-freeza/db stuff generally gets positive critical praise from everything i've seen.
one piece almost immediately got wholly positive praise from critics since its debut in viz's shonen jump years and years ago. the thing is, word of mouth and popularity gets people's attention more than critical acclaim. zach, how many crap movies break box office records while better ones barely register? i think it's better to hype one piece to anime fans with the 'this is bigger than naruto and bleach COMBINED in japan' spiel. most shonen/naruto/bleach fans seem to think bleach and naruto are as big in japan as in the U.S, and are way more prone to take the series seriously based on popularity than critical praise.
when bleach fans go, 'none of my friends like bleach! i bet when i visit japan('cause every anime fans is planning to visit japan some time in their life), everyone there will be a bleach fan!', correct them with, 'actually, one piece is way more popular over there. it's bigger than dragon ball right now! they even did a one piece crossover with dragon ball!' that usually gets people's attention.
it also helps to actual SHOW neophyte fans serious moments in the series. most people only have the 'silly' art as their only impression of it. i genuinely believe if cartoon network aired movie 4, movie 6, or strong world, unedited, one piece would get a huge influx of new fans from that alone.