When reviewing large numbers of issues, it would be very useful to see the last comment made in an issue (if any). This could be displayed in an issue navigator column. At a glance, one could review if any issues have been left "hanging" (last comment a question).
It would be even better if this "last comment" field could be queried, eg. "show me all issues in JIRA 2.6-dev not resolved and not last replied to by Atlassian staff".