@kmccormick Thanks for working on it. This is an important issue to me and many others. Personally I would focus on the reviewers who are approving these PRs. If the criteria for merging a PR includes that it has a description or follows the template, and reviewers are merging those PRs without checking that, then it’s likely they are not checking other things which are expected of a reviewer.
If someone is a “repeat offender” with approving/merging PRs that don’t have any descriptions or are missing any other important steps of the code review process, I think it would be totally reasonable for them to have their review privileges reduced for a while (e.g. their review is no longer sufficient for merge on its own, and someone else also has to review, until they’ve shown a consistent pattern again).