I agree with the sentiment that it's a risk when the writer can't get to the proper resolution in the right way at the proper span of time. But thankfully Oda has shown that he has no such difficulties. The series kills off so few characters that when he really wants a death to matter, he spends an entire chapter showing the audience, "Yes, he's dead, really, really dead" to let it sink in. He lets the consequences of character's decisions have their proper explanation without being heavy on exposition. There's plenty of showing and telling without an excess of either. You learn to hate characters you're meant to hate (seriously, by the end of the Baroque Works Arc, I REALLY hated every fiber of Sir Crocodile's being) and you love the character's you're meant to love, and the dynamics between them is always fresh and interesting.
The major difference between
One Piece and its immediate peers, I'd say, is the effort the author puts into research and planning ahead.
Naruto was really promising, then near the end it just kinda fell apart into a bit of a mess. Kishimoto was building the series towards a massive event, and some of the major loose ends of the series felt like they were left dangling just so he could clean everything else up for the series' finale.
Bleach... well, it's been kind of a mess for a long time.
Fairy Tail was always very simplistic, so it's never suffered much because its bar was always quite low so it was hard not to deliver. But Oda takes infrequent but timely breaks from
One Piece so he can do his research and have his much-needed vacations so each chapter can come out properly. On rare occasions he'll take 2 weeks off, and once, during the series' only time-skip, he took an entire month off to plan out the second half of the series (we're currently sitting at about the 65-70% completion mark, according to Oda). So similar to
A Song of Ice and Fire,
Once Piece is already planned out, it's just a matter of time before it's all PRINTED out. Though, unlike GRRM, Oda is quite young, and his work is constantly being produced consistently, so there won't be any complaints of large lapses in content. =)
But I just kinda get into the groove of "what happens next?" every week, so the time goes by without me noticing. I'd heard about
One Piece back in 1999, but I didn't get into it until 2006. So I've only been a fan for just under a decade, but it's always consistent and high quality delivered at a regular pace, and promised to be fully planned out, so I have few worries that it'll run into troubles like the other series mentioned above. Plus, major events like this don't come so often. Big ones come every year or so, sure, but not quite this scale! The last big mind-blow was the War of the Best (
Choujou Sensou) and that ended back in 2010!
I'm more concerned about works like
Berserk (because seriously, it's been a WHILE since Miura last released a new chapter) and
High School of the Dead, because apparently the brothers who collaborated on it have split and they haven't resolved what's keeping them from continuing it. Those are pities, really. =/
