We miss the reviewboard feature being able to see changesets based on different revisions of pull requests.

When reviewing and commenting pull requests there are often changes that have to be made. If the pull request is not small, then when the it is updated it's easy to miss things that have changed from previous revisions or to forget to check that problems commented on have been addressed.

I guess this feature is also closely related to:
https://jira.atlassian.com/browse/STASH-4263