It sounds like what’s being described here is essentially the Folgezettel concept from Luhmann’s Zettelkasten method. This could be an interesting feature. But I would want it to work natively in Markdown as much as possible so the capability is portable if I need to move away from Obsidian later.
One possible way this could be addressed is to base it around an outline note that follows a specific naming convention / location / whatever. Then it is doing nothing more than adding a visual capability on top of an existing Markdown file.
I already use sequential structured outline notes in some cases, for example:
- [[Note 1]]
- [[Note 2]]
- [[Note 2.1 (branch from 2)]]
- [[Note 3]]
...
Comments could also be added and made visible in the pathway, and encoded using a convention perhaps like this:
- [[Note 1]]
- Visible comment on Note 1
- [[Note 2]]
- Visible comment on Note 2
- [[Note 2.1 (branch from 2)]]
- [[Note 3]]
...
If Obsidian maintained these special Markdown files in a separate folder then we would always have the sequences encoded natively in Markdown to fall back on anytime later.
Counterpoint: Encoding the pathway in JSON in an Obsidian-controlled directory outside the vault ensures users won’t tamper with the Markdown and break the functionality. If Obsidian offered an export function that exports the JSON to Markdown that could work well too.