Potentially discuss (on wikitech-l?), decide, and document (where? https://www.mediawiki.org/wiki/Gerrit/Tutorial only quickly mentions -2) whether "controversial" changes should be marked as CR-2.
One outcome of T113378; I expect this to not happen too often though hence lowest priority.
Example: https://gerrit.wikimedia.org/r/#/c/231316 is -2 because "Needs significant thought before we consider merging this. Let's discuss that on the Phabricator task."