I want to say is to keep an eye out on Game Awards. Hopefully we might get something there
I'm willing to stand on this hill. It's only for the next 2 months anyways so why not have some blind hope? I'm not expecting it because I'm taking the finality of the Sora presentation seriously but at the same time there are just these little reasons I have to maybe consider it.
1. The 3 year anniversary at the VGA being where Smash Ultimate was kind of first let loose into the wild with Joker's reveal. What a bang to go out on? Sora is the final character wait... Who's that? Master Chief holy cow! Haha just imagine.
2. They already as a team committed to possibly working to end of December with the placeholder date. Maybe now that things are wrapping up in October they can work on an extra bonus fighter. A nice little holiday promotion for both companies and a seasonal gift for the fans.
3. Microsoft has a lot of incentive to push for this and would most likely fund the development themselves because the promotion it'd provide for Infinite would be deemed worth it and Nintendo likely could be brought on board for this for a character like Chief that could stand up to Sora's reveal just for a massively different audience.
4. Sora and Chief appeal to different audiences. Sure you could like both or neither but if you like one or the other it's very likely that if you don't like one of them then the other one you do like.
5. It's really weird how Halo's devs keep interacting with Smash speculation online. Yeah it's to dismiss it but most companies don't even do that because why would you? It builds hype and anticipation for your character anyways so usually companies just let the fans go wild with their imaginations. Maybe they're doing the good ol' Kirkhope bait and switch.
6. Maybe it's a Master Chief Collection coming to the Switch tie-in promotion like I've said. Pack the game with some Nintendo goodies like a flyable Arwing in each game and maybe some Metroid armor. Buy the game and get Chief free if you have Ultimate or buy him separately.
7. Maybe Vergeben ends up being redeemed and he actually got some crazy good info earlier than anyone else. It'd line up with the extra slot in the code or whatever that is I forget the details on that.
Of course the tagline is perfect for a bonus fighter too. FINISHES THIS FIGHT. Hell yeah!
All of this is obviously feverdream speculation for a game that's coming to an end that is so beloved that when it stops updating it actually gets missed. I will miss Smash. Having a little hope for one more for 2 months helps me in that process but it might not help somebody else in the same boat as me. Hype responsibly but basically I think just like you that anything else extra lives or dies at the VGAs.