@Mog:
Um, try looking at it as a separate piece instead of clinging to much what you know? I dunno, I'm guessing that's the reason people complain all the time. They don't like the style deviating too much from what they're familiar with? 
For me it's not so much the style changing, I just REALLY dislike that particular style. The line quality is terrible (thin little outlines that look someone ith palsy made them) faded colors, little to no shading, "over-animating" (droopy arms that just kinda flail about etc.). There's so many glaring "ICK"s that I have trouble focusing on how fluidly everything is moving.
EDIT:
I don't know about you , but when I look at this picture I see many glaring errors
First of all, Sanji's face looks like it's been crumpled up and then uncrumpled. Usopp's legs are waay to thin. Zoro's hip looks disjointed. Nami's missing some face and is in general off model. The lack of detail is not what I expect when I hear "movie animation". I mean, look art Robin, or rather I should say "the splotches of color that sort of resemble Robin". Luffy looks alright I guess, aside from that whole "lack of detail, faded/washed out colors and no shading" thing.
EDIT#2
@CosmicDebris:
And as for style being sacrificed, style DID have to be sacrificed in order to bring One Piece to the TV screen. They redesigned the characters so that they were more condusive to animating. In more recent times they've redesigned them again to look more like Oda's artwork. They're more complex and thus harder to animate. It shouldn't be a problem if they animators were more competant, but apparently at least PART of the time and part of the animation crew isn't very much…
i'm aware of this, as I said I'm not bothered by style change, I just don't like THAT…vomit up there