We are an agile software company that releases on a cycle of 3 sprints, each 2 weeks long. We can set our release capacity based on the # of development hours to determine about how many features we can commit to, but we also need to plan how many of those features or requirements can fit into each sprint (release phase) to help us prioritize within a release.
It would be nice if we could further add a release phase capacity and view how much total is used up or exceeded based on the features (estimates) that are linked to the phase.
Another nice-to-have would be for a view of a release with the phases and features included in each phase, to switch from showing the start/end dates to showing the length by estimates- at least if you're using Time for units. For example, when I look at the 6 features in Sprint 1, they are all lined up evenly unless i set each start and end date (which is TBD). It would be convenient to see them all starting at the beginning of the phase and display length based on units, so I can assign certain developers certain features back to back based on their total time, or at minimum which features to start first. (Hard to determine from Feature board since you can't tell which features are in which phases within a release.
Releases are meant to be used as time boxed containers which are used to launch a new customer experience. They can be used for releases, but also can be used as sprints.
Based on the description of your goals, it seems that using separate releases for each of your sprints might be a better route to go - as this would allow you to define and visualize capacity in the way that you are looking for.
Releases phases are meant more to be phases of a release (which can include both technical and non-technical work).
At this time, based on current priorities and community feedback, we are unlikely to make updates in this area, but hope that the suggested workaround can potentially work for you. We hope you can understand.