I looked at the ticket briefly a few days ago. There was some political discussion about the protocol license, and about various forks of the protocol. That might put a damper on things. As for whether it's officially planned, I haven't seen that stated anywhere. The best way to know is to look at the git repo, or better yet submit a patch :-) As you said, very few desktop clients support it yet, and it's a pretty new XEP. Tor Project is a nonprofit funded by donations, so I don't really expect them to be on the cutting edge of this kind of stuff. Actually, if I were them I might say "F it that's upstream's job, go bug the Instantbird developers" right off the bat.
I really think Ricochet is the way to go moving forward. If I had to guess, I would say quite a large percentage of the XMPP userbase is already using Tor anyway. XMPP lost a lot of credibility when Google Talk was discontinued. I think it's back to being a niche now. Case and point, you'd have just as hard a time introducing someone to XMPP as Ricochet, and the latter goes way above and beyond in protecting metadata. I'd rather see TP put all that effort into writing a Ricochet protocol plugin for Tor Messenger, and/or implement the Signal protocol on top of Ricochet. If you're careful you might be able to make Ricochet and XMPP with OMEMO interoperable using an XMPP transport/gateway.
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