I think everyone here is realizing just how annoying stall is in this meta. We have a tier where you cannot use attacking moves and somehow this tier is still more stally than that. I don't think stall is "broken" because there are definitely ways to beat it, but they all require huge team building limitations that make you much weaker to other team archetypes, such as weather HO.
Fur Coat + Ice Scales turn already traditionally good mons into absolute hard walls. While yes, both Frosmoth and Persion-Alola aren't good mons, effectively doubling the health of your entire team completely validates putting them on any stall team. Stall is made even better by the fact that Unaware is not banned. With Unaware on the enemy team, all of your set-up based stallbreakers become pointless. While Unaware doesn't ignore power boosting abilities or items, it can still make every game halt to a near complete stop instantly. Lapras is also a point of discussion since it becomes able to remove most problem mons for a stall team/
Another ability to mention is Pressure. Probably not broken, but Corviknight is a pretty popular mon for it's movepool, typing, and stats, so this ability isn't very uncommon. I did go against multiple teams where they were built around PP stalling, and while Regenerator and Magic Guard were banned, this is still very annoying to go against. While Pressure can be run against stall teams to help counteract this, it just doesn't seem good to keep an ability around that could often lead to games ending with Struggling back and forth. Again, probably not broken, but definitely seems unhealthy for the metagame on paper.
Simple seems very powerful but is turned into a complete gamble to have on your team because of Unaware. Unaware makes every set up spam team pointless. If Unaware is banned, Simple should also be banned alongside it.
Weather is really strong. Rain is probably the best because it has great mons like Crawdaunt and Dracovish. A water immunity can be run, which is generally a good way to slow down rain teams, but it's still not fun to lose to a rain team because you didn't have a water immunity. The same can be said about sun teams, which run great mons like Darmanitan and Rotom-Heat. The problem with these team archetypes is that they form what is basically a game of chance. A game can be lost at team preview if your team isn't packing [insert mon here]. Obviously it's impossible to make any team that can counter every other team, but you can typically try to have a good matchup spread with as many mons in the tier as possible. With the current state of the meta, almost every team is stall, weather, or a ton of boosting abilities. It's very difficult to cover all of these matchups in a team, as typically you need mons that are not that good and waste a team slot. An example is Cloud Nine on Drampa. Drampa isn't incredibly useful in an OU based tier, and I shouldn't have to explain why. Same with immunities, but there are actually good mons with immunities.
All of these factors have caused one very noticeable trait on the ladder. There isn't a whole lot of team diversity, and there is very clearly amazing must have abilities/mons on specific team archetypes. I think the tier is super fun, but it definitely needs a couple things banned. I really am unsure on what I would ban about weather, if anything at all. I love weather teams, but they destroy many teams that are unprepared, which is many. Right now it's probably Rain>Sun>Sand>Hail, but it's still very difficult to prepare for all of them. Obviously hail sucks but if Unaware gets banned Veil HO teams could become the new wave with Simple, and MAYBE Slush Rush.
These are just my thoughts on the current metagame, I love this tier, but damn does it have some issues. Weather is ALWAYS polarizing in Pokemon, and so is stall. I think there are some weather abusers that should be looked at a bit closer, and I think Unaware + Simple should be banned. After Unaware gets banned THEN I would look at Fur Coat + Ice Scales since many stall teams could be broken down by a set-up stallbreaker at this point. With these bans/changes I think it will be a much healthier metagame with less restrictions on teambuilding.