A season and a half later...I think the show has definitely improved since season 6. Back then the new cast felt very artificial, with no chemistry.
Now we have this new group of Meredith, Cristina, Alex, Avery and April that is not perfect and as entertaining as the MAGIC was...but it makes sense, they've built credible relationship (that in the case of April means being the joke around).
But I do think they should write off some characters so they can develop the important ones. For example, Teddy's stories doesn't involve any other characters apart from Owen and Christina. I don't say she shouldn't be there, but not as a regular.
And Lexie is such a waste of a character...they don't give her any storylines apart from her affairs with Mark and Avery. They don't let her develop her own personality. Seems like that's changed with her working with Derek, but this is her fifth season and still feels like she's a newcomer.
Anyway, they'll have to reduce the cast soon, because in no time the show will be too expensive for the ratings it's pulling.
Oh, and as unpopular as it may sound, for me this is just yet another season in which Private Practice is proving to be way better than the mother show (leaving their differences apart). Grey's got to higher highs in the past, but PP has the consistency the mother show lacks.