I really like the NextGen Projects and JIRA Roadmap! Wonderful enhancement to JIRA and I believe, it's really next gen!
But, I miss to have a Backlog view combined with both releases and Epics!
I badly miss also the possibility to enhance releases in the roadmap as well as the tree level view of Epic - Story - SubTask.
And another point I would add: simply sort tasks underneath an epic in rank. This would give a very great overview.
Please continue developing in the Cloud! Great work!