I have it from the horse’s mouth (Licat’s) directly:
Preserve links after renaming headings has already been implemented - you just have to trigger the rename using the right click menu on the heading. Blocks don’t get renamed often so we haven’t prioritized it.
My reply:
The right click trigger is not workable in practice. You have to remember to do it. It should be an automatic thing, like the automatic adjustment of links when file names are changed.
Licat’s explanation:
Unfortunately, monitoring heading changes automatically is impractical from a performance perspective. Automatic rename would mean that the program has to constantly monitor what you’re typing in the document.
Constantly checking if you’re editing a heading or not a heading, whether that heading has references to it. It also doesn’t know when your rename is finished.
So, that means this feature request will never be implemented natively in Obsidian. @WhiteNoise can therefore close this topic.