I prefer the Tate/Sonoda team, some of the best episodes the series had.
Best action directors is Makoto Sonoda and Takashi Otsuka.
Tsuyoshi Koga is great, I love how he delivers the jokes. Comedic episodes are his strength.
Aya and Tokoro does magic to the slow pacing, mostly.
My favorite One Piece Directors:
-Takashi Otsuka
-Makoto Sonoda
-Tsuyoshi Koga
-Katsumi Tokoro
-Sumio Watanabe
-Hiroaki Miyamoto
-Komaki Aya
-Konosuke Uda
These guys are also good:
-Tetsuya Endō
-Yutaka Nakashima
-Naoyuki Itō
Only Takahiro Immamura and Yoshihiro Ueda that are really terrible.
–- Update From New Post Merge ---
Okay, so Satoshi Horisawa told me that he is not working with Shimanuki on #606. So it might mean a slightly different staff. According to the rota, it's about time for Tomita to show up, I really hope he is not thrown in randomly in #605, I hope he is being saved for #606, well unless he is helping out with the Merry Special.
Yukiko Nakatani working on #603 means she is not completely busy with the Merry Special, so she is helping with some KA.
Yukihiro Urata was the 2nd main animator on the Nami Special, if he doesn't work on the next few One Piece episodes, he might be involved with Merry Special.
! 2012
April = HxH #28 [Last work]
May = [MIA]
Jun = [MIA]
July = [HxH] [Returns]
! 2013
May = OP #594 [Aired May 5th, so he should be MIA in May as well]
Jun = [MIA]
July = [MIA]
! He didn't animate anything in June, probably working on the Merry Special. He usually have something every month.
Kenji Kuroyanagi doesn't seem to be on any other show at the moment. Last thing he worked on was Toriko's second Opening.
! 2012
April = OP #545 [Leaves]
May = [MIA]
June = [MIA]
July = [MIA]
Aug = [MIA]
Sep = OP #566 [Returns]
! 2013
April = Toriko Op#2 [Leaves]
May = [MIA]
June = [MIA]
July = [MIA]
! Could be helping with Toriko movie, if not, then Main animator on the Merry Special. I certainly hope so!
I'm not sure about Ryo Onishi or Naohiro Shintani, since they are probably involved with movies. But Last year, they were working on Film Z. This year, I don't know what they are busy with, but man I really hope it's the Merry Special.
BTW, #603 had some new animators, I think from studio guts. I couldn't find info on the new guys. Anyway, I thought most of the episode had good animation. Nothing mindblowing, but definitly some above average moments.
I find it funny that 2 of the best Animation Directors in One Piece do KA on the same running scene, Ishizuka in #602 and Nakatani continues with #603. lol