I found structural discussions took place in the free form areas of mondrian, and knit-picking was a direct result of two aspects: 1) An strict, but oft changed style guideline 2) The requirement to say something beyond LGTM to prove that the code review was thorough.

The one aspect I missed at Google compared to other large software companies was design document reviews. I found that in writing and disseminating such documents a lot of good work was done.