I use the release->roadmap view a lot. But I put in my own Features as the "phases" So I think my request amounts to putting in a "percent complete" field into the Feature, and having that value appear in the Gantt chart in release->roadmap.
Thank you for the request. The releases roadmap screen currently has a view option which allows you to color bars by status. This can allow you to depict the status of your features directly through the bars. Its also possible to recreate a similar chart through the use of custom fields and the Report Timeline page.
Based on the workarounds noted above, along with current priorities and community feedback, we do not have plans for additional updates in this area. We hope you can understand.