[TeMPOraL]

> FWIW, this specific feature - what they are now calling sub-issues - is actually better described as a framework for modeling proper parent-child relationships in their system, which is something quite hard to get right

That's a wrong framework to use. Parent/child relationship is a special case of dependencies between tasks, which can be more generally modeled as start/finish relationships, i.e. one of: Start-to-Start, Start-to-Finish, Finish-to-Start and Finish-to-Finish; parent-child relationship is Finish-to-Finish here. This distinction starts to matter if you want to plan out more work items than you can quickly eyeball on a Kanban board, and it's all well-trodden ground with nearly century worth of prior art, to which our entire industry is entirely oblivious.

Useful search terms: PERT, Gantt charts, critical path, PMBOK.

Popular software occasionally spotted in use in our industry (usually by PMs, in secret) that supports it: MS Project, maybe Jira, ... is there anything else?

[ec109685]

Once you have sizing, the ability to make an issue dependent, estimated start / end, don’t you have everything needed to generate a PERT / Gantt chart?

[TeMPOraL]

You also need the proper dependency types[0] I mentioned, though I'd say you can get away with FS for dependencies and FF for subtasks.

Beyond merely generating a Gantt chart, when you have dependencies and estimated duration you can start estimating how long things will take and which ones can take longer or be delayed without impacting overall project time; add the ability to provide constraints on start and end time, and you can automatically schedule work (and re-schedule at it happens).

Most of these things are in every system in some form or other, but dependencies seem to be missing almost everywhere - and dependencies are the one key component that enable major benefits and turn the system into a proper project planning tool.

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[0] - https://en.wikipedia.org/wiki/Dependency_(project_management...