When commenting an issue the comment's header looks like this:

If the issue is within a project that has a lot of transitions in its workflow it would be nice to know if comment was given when doing a transition.

Thus, new comment header should look something like this:

Now it would be easier to see with one glance who has done which transition and with what comment. This information is quite hard to get if there are many comments and many transitions (there is Transitions Panel which helps a little with this problem). I believe that my proposition would be simple to implement and really usable for many JIRA-installations.