I think it would be nice to be able to see the reason for an edit without having to click through to the diff to view it. I think it would benefit users to be able to see at a glance whether the edit was a clarification, rewrite, or simply a small typo/formatting change.
Two ways I see to do this:
Show the reason on the same page under the edit time:
edited 1 hour ago
Show the reason in a tooltip when you mouseover either the word "edited" or the entire edit notification.
Do you think this would be beneficial? How else would you propose to do it?