WordPress, Ulysses, and Integration
What I personally find frustrating is that the UI of the Ulysses doesn’t make it clear that “publish” feature on the app is actually an automated export feature, perhaps even a glorified one. While you can “update” a post, —the actual terminology used in the app—, once the link is broken for whatever reason, the app doesn’t notify the user of this fact at all and will try to publish it as a new post; its default behavior is to publish, and it treats updating as irregularity. I can’t speak for all WordPress users, but I would argue publishing a duplicate post without a fair warning is a concerning behavior.
That being all said, it does make me wonder if WordPress system is as expandable to begin with. After doing some research, I found out the core issue lies in how WordPress manages its DB, mainly how there are no ways pinpoint what IDs are assigned to each posts, comments, and etc. On the surface, it is helpful that I can simply publish another post with the same slug, and the readable text will be the main interface. On the other hand, that’s not how the actual system works, and the idea that it’s swaying even the advanced users away seems ironic.
Ultimately, I decided it would be far better if I leave the old posts as-is, and simply link a new post using trackback. I understand trackback is controversial in its own right, but being able to create threaded posts in effortless manner always helps. And I would like to emphasize that you can contribute your part of the discussion via trackback as well; create a simple blog on WordPress.com or service of your choice, —it may even be free— and link my post in yours. It will automatically send trackback request.