I thought that 4th wall breaking may have been the worst moment of the series and I'd actually rank this season as one of the worst. My biggest problem has been the normalizing of Erin, where suddenly all her quirks have been removed as the writers try to throw in yet another love triangle between her, Andy, and some guy whose sole existence up until now has been the new guy no one pays attention to. The previous seasons had their flaws, but Erin was consistently hilarious whereas now she's been turned into another Pam.
I like Ellie Kemper, and enjoyed Erin when she was introduced, but her character started to wear pretty thin for me last season, mostly due to the fact she was being written as naive to the point of almost barely functioning as a human being. I agree she's sort of gotten the short-end of the plots/scenes this season, but I'm kind of indifferent to those circumstances.
As for the 4th-wall breaking, what I appreciated about it was that they finally acknowledged the fact that this documentary crew, after almost a decade of filming these people, has not just been sitting back as passive observers, but have actually become involved in their personal lives. Within less than a minute, they were able to convey just how emotionally invested these people are with one another. In the era of all these mockumentary-style sit-coms, which often make little-to-no sense when you think about the content of some of the scenes, it was actually a relief to have Daniels & Co. acknowledge the artifice of the concept and the eventual bond between observer and subject matter that seems inevitable within the context/length of the show. Now, honestly, I'm not that confident that this will result in good material for the show going forward, considering having the documentary filmmakers become characters on the show could get really tired given the number of episodes that remain this season. I also could be completely out in left field on this one, but that's not surprising since I'm one of the few that love the California episodes of Mad Men