When a certain change, no matter how minor, requires further actions from the communities (for instance changes in Common.js/Common.css), that change should be communicated on wiki, along with clear expectations of the changes to be made and, if possible, an example.
It would also help if such changes could be evaluated after a while: how many communities did make the change? For the communities that did not make it, what was the blocker? Did they start a discussion following the announcement? Did they work around the new feature to disable it? Are they dependent on a single person who was not available/willing to make the change? On the long run, this should lead to upgrades to this guideline.