Somewhere up above, Pabloaram made the point that using the logic of “broken checks broken” is an inherently flawed line of thought in this metagame, and I’m inclined to agree. UU as a whole has been in a fairly unprecedented position throughout the entirety of SS due primarily to dexit and then the subsequent shakeups of Home and Isle of Armor, as well as Crown Tundra in the future. With this in mind, I think the council has done a pretty good job of maintaining as much stability in the tier as they can. Post-DLC UU is incredibly offensively oriented, with such archetypes as bulky offense and hyper offense being very common throughout the ladder. Stall and balance are still prevalent of course, especially with the dominance of Skarm/Bliss as a defensive core and the ubiquity of teleport Slowking. That said, even these strong defensive mons are not infallible, and there’s a reason that certain mons were sent to the shadow realm.
It’s understandable that lots of people might be interested in retests now that the dust has settled a bit and things have started to stabilize—at least to some extent—in the wake of the many drops we got. However, we saw firsthand recently that Durant especially is still too strong and unhealthy for the tier. Things like Alolatales aren’t unhealthy because of their offensive presence, but because of the type of metagame that they encourage. In a wallbreaker-infested tier, Aurora Veil is ridiculously good, to the point where it is absolutely centralizing if there is a mon that can abuse it with the efficacy that Alolatales can. I’ve seen the argument that with the reintroduction of Venusaur to the tier, Alolatales will balance out the inevitable return of sun as an archetype. I understand this line of thought, and it does make sense in a vacuum. But in the broader sense of the tier’s balance as a whole, this simply wouldn’t work due to the archetypes that Alolatales’ presence encourages. We’ve seen how crazy hyper offense teams can be with Grimmsnarl’s premier dual screens support. Now imagine that but in one turn, with added chip from hail, plus sleep with hypnosis support? It’s no wonder that Alolatales was banned in the first place, and why it still is now.
As for other mons people have pushed to be retested, I’ll touch on them a little bit too. Dracozolt could be more manageable in theory now, with the prevalence of faster mons in the tier as well and the power creep that has shown up post-DLC. That said, what scarf Zolt sacrifices in power, it gains in speed. That in combination with tailwind support from teammates such as Talonflame, allows Band/Scarf Zolt to shred defensive staples such as Slowking and Skarm. Zolt would only really be stopped by Steelix, but even then, it could run High Horsepower for a clean guaranteed 2HKO. I can see why the council chose to keep Zolt banned.
Haxorus is Haxorus. It’s now gotten a new tool in scale shot, which boosts its already insane walkbreaking capabilities even further with the speed increase. Most of what I would say about Haxorus has already been said, and probably better than I could articulate, so I’ll keep it to this.
Primarina I could honestly see finding a somewhat healthier spot in the meta than its UUBL companions. Given that its physical defenses are lacking, it certainly doesn't appreciate the level of physical strength in the tier. That said, its stellar offensive typing in conjunction with specs or calm mind allows it to shred unprepared teams. Its typing also lends itself to some useful resistances as well. I could really go either way with Primarina. As much as I love the mon, I can see why it’s not been retested quite yet.
To finish up, I just want to reiterate that a mon doesn’t have to be offensively ridiculous to be broken. Alolatales is broken because of the type of metagame and archetypes it encourages. Other powerhouses like Dracozolt and Haxorus are more unmanageable because in the former case, it lacks defensive counterplay with proper support, and in the latter case, is incredibly hard to stop once it gets going. I think a lot of people think about UUBL retests both in a vacuum and in the mindset of “broken checks broken”, which, as I’ve hopefully illustrated with the points on Alolatales, is a very dangerous line of thought in the kind of metagame we’re in.
