Unsupported Use Case
During my own personal heyday of WordPress usage, I’d always wanted two particular features: a way to add updates or addenda to posts such that they automatically had their own timestamps and were their own database items, but attached, so to speak, to the posts they are on; and an easy way for old posts to list new posts which link to them, without having to open up to external trackbacks or pingbacks (or, now, webmentions). It always had seemed to me that these were pretty damned close to being no-brainers, and that they’d be features used widely if implemented, whether in the WordPress core or through plugins. I’m honestly surprised that in the decade or more since, these features still do not exist. My entire life, sometimes, seems defined by being an unsupported use case.