Generally speaking, epics are not well supported in roadmaps. The main pain point for me is the inability to display release, phase, & epic in one roadmap. I instead need to create multiple reports to view what should be visible in one centralized view.
The starter roadmap & release gantt force you to toggle between release and epic. I would like the ability to see epics nested under releases like you can for phases and features.
The custom roadmap view is cucumbersome when trying to achieve this view. If I populate the bars with release, phase, & epic I get something like this...
Release 1 | Epic A | Phase i
Release 1 | Epic A | Phase ii
Release 1 | Epic B | Phase i
Release 1 | Epic B | Phase ii