Diff between branches/tags ability

Our company could benefit from a way (within stash) to see the differences between any given branch head and/or any given tag. This would be beneficial for our release managers that have not real reason to clone the repo as they are not programmers. More importantly to them, would be the ability to see which non-merge commits were contain in the diff set. For example:

Our release managers ask the question. "What JIRA issues were addressed in the 0.7.7 to 0.7.8 update?" It would be nice if there was a way they could simply log into stash and generate that list for themselves. If this list can be generated with a REST call, that would be icing on the cake.