It would be beneficial to allow (during manual stage triggering) for the definition of required/optional variable inputs that would be provided by the user who triggers the stage.

For example, one of our manual stages is to post the build artifact as a release download. Once this has completed, we have a script that runs out and determines the next development version (ie. when releasing 1.4.4, it might be 1.4.5, or 1.5.0, etc.) and updates one of our build files.

When triggering this particular manual build stage, it would be nice to define an input/variable, say "Next Development Version" / $nextDevVersion that could be provided by the user (via a dialog/text box when triggering the stage), and be made available in tasks for that particular build or stage.