Well they can't exactly get ahead of the manga. Another thing I noticed is that they end the episodes at odd moments, like in the middle of a chapter. The new episode should have ended with Bege throwing the invitation at Sanji and then revealing his name as Vinsmoke.
I honestly wouldn't mind a well thought out filler arc. Even a long one. I really enjoyed the G-8 arc. If a longer arc could be made like that it would be awesome. I stopped watching the anime tho because I don't like watching a scene zoom out with dramatic music for minutes at a time.