We enabled Diffusion in https://phabricator.wikimedia.org/diffusion/ with the intention of getting a code repository browser. And we got that, but we also got a full fledged "Audit Commit" form at the end of every commit page, including concepts like "Accept commit" and "Raise concern". We have never used Audit, it is not even installed in our instance.
As a community we haven't discussed the possibility to open a new channel of communication for post-commit code review. We love Diffusion, we want to get rid of GitBlit thanks to it, we are importing new repositories every week... but we want to get rid of those forms as soon as possible to avoid confusion with our actual code review process (pre-commit, via Gerrit until the day we figure out our migration to Differential).