One thing that would be fairly easy: Bedevere could automatically add a label to any PR that touches What’s New. This would be an easy way for anyone to filter open PRs based on what’s about to be new. Github also has some beta feature enabled for the Python organisation that lets you receive notifications based on labels.
(assumptions: most changes we want more visibility on merit What’s New entries; we do a reasonable job encouraging contributors to add What’s New to relevant PRs; we want a mechanism that increases visibility before merge)