I'm not the biggest UU player, but I'm gonna leave my thoughts on these four guys:
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Zeraora is an interesting addition to the tier, it brings some good offensive presence with an excellent coverage and an amazing speedtier, its offensives stats are far from incredible but definitly great, even more when coupled with a Life Orb. It's coverage might be actually too great, from S to A- rank, there is only one "counter", which is Altaria but loses to some Iron Tail variants, from B+ to B-, there is only one counter, Chesnaught, but is not too splashable right now due to Latios and its Mega form being everywhere. Of course there are good checks, M-Lix, M-Aggron, Rotom-H, Kommo-o, Scarf Krookodile, Gligar and Nidoqueen, but I could see it staying because of a shit 4MSS and the lack of raw power. (edited cuz i didn't c/c the good text i'm so dumb)
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Bisharp is back, and it's definitly a nice addition to the UU tier, I used it in 8 or 9 games today, but I already have something to say about it, Bisharp is a top-tier threat but is far from broken, it's really hard to handle when it setup an SD, but it can be easily revenge killed by fighting-types which are already dominant in the meta, Terrakion, Infernape, Cobalion (which is also a counter), Kommo-o, Heracross, Mienshao, Toxicroak, Lucario etc... In terms of defensive awnsers, there is M-Aggron, M-Lix, , Cobalion, Hippowdon, Chesnaught, Bewear, the two Unawares water, and that's pretty much all, I've seen Low Kick variants to punish some Cobalion, M-Lix and Bewear switch-ins, but it loses SD, so it's cleaning potential is reduced a lot, I personally don't think it's broken by any means, but easily one of the best mons on the tier.
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What if you take one of the top 3 mons of UU, make its offensive presence better ? That's right, it does Latios, and it's easily one of the most threatening mon out there, it does the same shit as Latias but better, CM + Z-Move Latias ? It's now Latios' property. Specs is imo, the best set that Latios can run, like wth there is no switch-in to this beast, Specs Draco does around 50% to bulky Scizor, which forces it to Roost, so you can switch freely into another threat. There is no actual counter to Latios, it doesn't shift the meta like Zeraora or Bisharp does, but idk, I think giving Latios some time in UU then suspect it after might be a better idea just to see how the meta evolves, but I'll totally understand if it gets quickbanned.
(edit: tested specs a little more, fucking ban this thing)
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What if you take an already incredible mon and make it bulkier ? Mega-Latios. Calm Mind + BoltBeam with Roost is actually so hard to deal with and might be it's best set, it can break defensives cores so easily, and thanks to that additional bulk, it's actually so hard to revenge kill, Scarf Krook ? M-Tios takes ~50% from Knock Off and Ice Beam the shit out of it, Bisharp is your check ? Ok, just get predicted once and it's now dead. Draco from Scarf Hydreigon or Scarf Lati ? Ok it can just Roost off the damages. The only good revenge kill is actually Beedrill and is not the biggest thing to get rid off, it's the typical low-risk, high-reward mon and I personally think it's too overwhelming for the UU tier and should be banned.