Since it's my comment, I want to try to explain why I did it, and what I hoped to accomplish. The edit I made was an aggressive edit which was more than cosmetic changes to the post. When you make aggressive edits, not everyone is happy about it. To try to minimize the anger, and still be able to improve question quality, I leave a custom comment trying to show the user:
- I've made a big change
- I'm doing it to help them out
- They are more than free to fix it if I screwed up
This tends to be effective (out of the 27 aggressive edits in the above meta post, 13 have received non-negative comments, and only two got negative comments).
If I'm making a cosmetic edit (like editing the tags, or fixing a formatting/spelling/grammar error), then I don't think the message is necessary in general, since I haven't seen many users get bent out of shape over someone proofreading their post without a comment.
In cases where a significant change is made, I don't think any cookie-cutter fixed comment will have the same impact as one made to explain the reasoning behind it. In cases where an insignificant change is made, I don't think that a comment is required in the first place.
If you want to implement this, then I'd need to know who the target users are, if this would be the best approach (compared to a message visible only to the original asker that points them to guidance on our edit policy and how we are different from a forum, for instance), and what the messages you recommend adding as auto-comments should be.