6 is an arbitrary score for the whole season. This episode was better than average, but had the same essential flaw, essentially summarized by that old saying: too many cooks spoil the broth.
(Same) four writers for every episode this season, as opposed to just Larry David for the previous 7 seasons. No slur whatsoever to the other three, but very few classic sitcom episodes have ever been devised by four people. And the previous 7 seasons had quite a lot of classic episodes.