We're excited to announce that the ability to split issue is available in JIRA Software 7.5 starting from today!
We really appreciate your patience with this feature request, and apologize for our silence on the matter. We also appreciate the insights in this thread - it helped a ton in the design and prioritization of split issue.
Merging issues is really a separate feature request which we'll prioritise independently and is tracked in JRASERVER-3592. In hindsight we should have separated the two a long time ago, but we promise we will use all the comments around resolutions from this suggestion in the design of the feature, so no need to put the same comments, just make sure to vote and watch the issue! We will provide further updates in there.
As we've mentioned before, our Cloud and Server deployment options are now on separate roadmaps (read more here), but split issue is a great example of a new feature shipped in cloud, that was popular and prioritized with server customers, that we have brought into server.
JIRA Software 7.5 is now available to download so you can start planning your upgrade straight away!
Learn more in our release notes.
Product Manager, JIRA Server