Money quote: "Nothing should be surprising to a reviewer in a code review: discuss any significant design decisions before code is written. Code reviews are a time to iron out implementation details, not discuss major design or architecture decisions."
What if you use pull requests to prototype architectural change? My take is your pull request should include the context of the change and the sort of feedback you want.
Money quote: "Nothing should be surprising to a reviewer in a code review: discuss any significant design decisions before code is written. Code reviews are a time to iron out implementation details, not discuss major design or architecture decisions."