Looks good. I made one change, which was just to remove the "Reason it's..." labels when it's not the author. I think the description, if it's there, along with the context of the banner will be enough.
Fixed an issue that close description didn't show to other users
Review Request #2463 — Created July 10, 2011 and submitted
Now, non-empty close descriptions will show up regardless of users' permission. However, it will become editable if users have permissions to do that. This change should go with review 2461.
Manually tested. Logined as users with different permissions and anonymous users. The close description showed correctly.