It would be nice for normal users to be able to change the text of an edit summary after it's saved. Obvious uses:
- giving proper attribution for text imported from other sources
- correcting typos (eg redlinks)
- retracting offensive remarks
- improving poor or unintentionally misleading summaries
Downsides? There would be some loss of traceability, if one user accuses another of having said something offensive in an edit summary, which is now not apparent. Perhaps all changes could be written to an admin-viewable log in case of disputes.
Sorry if it's been suggested before, I did look.