I'm very glad to see UUbers Ubers UU get on Smogon! I'll start off some serious discussion:
I am a stall player. After the last tier shifts, where Giratina, Gliscor, and Dondozo rised, and Baxcalibur dropped, stall became way harder to build, way worse, and far fewer people are using it. It's to the point where I believe that stall is bad to a unhealthy degree, and nobody wants to play it.
In my view, the primary reason for this are the three main physical attackers: Zacian, Baxcalibur, and Palafin. Without tera, there is no pokemon that can reliably beat all 3 of them, which means you either need 1 pokemon to beat each of those or you need to dedicate your tera whenever you fight them, which is really bad as they're all common, and still means you lose if they have multiple of these pokemon.
To add insult to injury, the 3 pokemon you'd use to counter them are generally fairly bad for stall, and you wouldn't use them otherwise. This tier is primarily special attackers, which means that the three physical walls you'd have generally aren't very useful outside of that matchup beyond a few specific pokemon, like physical Arceus forms. This constrains stall teambuilding massively: If you want to be able to keep your tera, which is very important, then 3/6 of your team is locked into otherwise mediocre pokemon.
What do you all think should be done about this? In my view, with the tier shifts just a few days away, I don't think anything should be done until the tiers shift. However, if the tier shift happens and nothing significant changes with this dynamic, I believe that either Zacian or Baxcalibur are banworthy. While they likely aren't banworthy ignoring stall, they both make stall so hard to build that it's essentially extinct beyond me and one other player, and pokemon invalidating an archetype seems like a fair reason to ban them to me.
(I don't think that Palafin-H is banworthy in any situation, unlike the other two, as banning it would destroy rain.)