Just to show my homework that I've thought about some of these problems at least a bit more than just surface level, and as an interesting aside to anyone exploring the topic: Starting from UX/workflow as the end goal, at one point I was wondering if branch level issue information should be stored "purely" as CRDT/OT-style deltas accumulating append-log-only in place, and all UIs (including a CLI) building a gestalt from every branch to get individual issue state. Which is a lot harder to build than just "store a database in each branch, query the database as needed, UI is a basic CRUD app". That is, though, closer to the intuition of stakeholders that there's only "one" issue in a constant state of flux/collaboration, rather than one issue per branch (pending merges) per repository.

Again, all of that is theoretically possible. (We've got CRDT/OT-based collaboration apps all over the place today.) It's certainly not easy though.