Hi @alemi, timely reply!
I just published a “state of the union”-style summary of what’s been going on around context
(Although since I’m posting on SocialHub, perhaps I should post the SH link instead: The state of conversational contexts (February 2025))
There will likely always be implementors who use context via opaque string comparison. We should allow that usage due to prior art.
With regard to an inconsistent context, my opinion is that if your software supports resolvable contexts, you should attempt to inherit the resolvable context closest to root level. Otherwise it is perfectly ok for you to generate your own context or not use one at all (again, prior art.)
context being a link to the first note makes sense, that could be a valid use case for context as well. The ForumWG has no interest in forcing only one usage of context (as @eprodrom noted many times, doing so would violate the original intent of the ActivityStreams context property.)
Traversing the replies collection is lossy, if you encounter a dead node, you lose everything below it. Likewise if you traverse up inReplyTo and encounter a dead node, you lose everything above. So there are reliability concerns. I have no specific opinion on its scalability yet, although I know Mastodon is interested and looking at a PR implementing this.