Bewear looks neat, haven't played with it but it looks like people are coming to terms with it so that's nice since that'll give the tier a way of dealing with some obnoxious mons like Feraligatr. I'm here to talk about something else, though.
This piece of trash. I feel like there are plenty of mons in the meta that deserve closer inspection, but one thing that needs to go for sure is this thing, imo, and for one reason: the fucking Calm Mind set. Sure, the OTR set exists and it's good, but you never really see that and we all know why: the CM set is just that much better. This set is absolutely busted for several reasons:
1: Gigavolt Havoc. This one's the elephant in the room, obviously. In a world without Z-moves, Reuniclus would have serious coverage issues, since you'd usually either opt for Shadow Ball and get walled by several Dark- and Steel-types or use Focus Blast and find yourself in trouble against opposing Psychic-types and Doublade. Thunder would be a more niche option, hitting more targets neutrally but lacking the power to bust through Psychic resists and being too inaccurate and low on PP to be really reliable. Gigavolt Havoc gives Thunder the oomph that it so desperately needs, essentially functioning as a high-power STAB move with no drawbacks, giving Reuniclus the power to smash through a lot of sturdy Pokemon that under other circumstances wouldn't fear it as much. For example, Umbreon would be a decent check since between stalling out Recovers with Foul Play and tanking even +6 Thunders decently thanks to its raw bulk plus the ability to use WishTect. A well-timed Gigavolt Havoc, however, destroys Umbreon, making it a shaky check at best. Water-types with Haze are also way more pressured thanks to the possibility of Reuniclus throwing a very powerful Electric-type move their way. More importantly, however, more offensively minded checks that would otherwise be able to stomach a hit from Reuniclus with relative ease and OHKO or 2HKO now struggle with it quite a bit more. Doublade is a top-tier mon that with its standard spread comes close to 2HKOing Reuniclus and can tank a +1 Thunder or even two from full (not recommended though), so it seems like a decent check. However, Gigavolt Havoc at +1 makes it way easier for Reuniclus to break Doublade, as it does ~75% at worst, and everyone who plays this tier knows it's not too difficult to chip Doublade to the point where that's an easy OHKO. These examples may not seem significant an sich, but keep in mind that without Z-moves Reuniclus couldn't reliably beat all of Umbreon, Doublade, and bulky Water-types (as well as a slew of other checks) with one set. The fact that it now can do so makes it way harder to prepare for Reuniclus, and it never was an easy mon to prepare for to begin with.
2: Magic Guard. This is old news, but still as relevant as ever, since unlike most sweepers, Reuniclus can't be stopped in its tracks by a well-timed Toxic simply because its ability ignores that entirely. Other bulky sweepers need to go down the RestTalk route or use Heal Bell if they get it, which usually means they won't have room for a coverage move and restricts their effectiveness, but Reuniclus has no such problem. In addition to this, Magic Guard also makes it difficult to beat Reuniclus by playing aggressively, since it never takes damage from Stealth Rock and therefore hardly minds that you double switched into Heracross and forced it out. You can just come back in later. This also means that failing at sweeping with it and taking serious damage doesn't have to mean the end, since even a Reuniclus at 30% or whatever has the bulk to come in on a wall and Recover, even when Stealth Rock and three layers of Spikes are on Reuni's side of the field.
3: Bulk + lack of weaknesses. Reuniclus is very physically bulky and after a CM or two practically impossible to kill on the special side. This means that even strong neutral hits often fail to (revenge) kill Reuniclus. Flygon's Devastating Drake, for example, fails to even hit 70% and can be Recovered off (not to mention you don't want to waste your Z-move on an attempted revenge kill to begin with); Mega Glalie's Double-Edge struggles to even do over half; Feraligatr's Crunch does 61% max and I don't have to tell you what happens when it gets hit by a Thunder. While a combination of these hits + some other strong attacker will be able to bring down Reuniclus, these simply aren't reliable answers and you usually have to let at least two things die before you can revenge kill Reuniclus properly (and like I mentioned before, nothing stops you from switching out and trying again later). Supereffective hits, meanwhile, are hard to come by. Reuniclus may be weak to Ghost- and Dark-type moves, but those types lack strong attacks that can actually break Reuniclus. The best physical Dark-type moves is Knock Off, but due to its Z-stone, Reuniclus takes reduced damage from that. Ghost-types, meanwhile, have.... Shadow Claw as their best option, which is obviously quite weak. Bug-types like Escavalier, Heracross, and Durant (X-Scissor isn't even very good on Durant) are the only ones that can actually destroy Reuniclus, and Escavalier is the only one that can switch in more or less safely.
With these things combined, Reuniclus lacks both adequate defensive counterplay and proper offensive checks, stifling teambuilding and making it incredibly difficult to beat. Other than the aforementioned offensive Bug-types the only things (not literally but pretty much) that reliably beat Reuniclus one-on-one are Taunt Umbreon, Skill Swap Cresselia, and Curse Quagsire, all of which are either niche sets or only fit on a specific kind of build. Many a ladder player has been relentlessly 6-0d due to not knowing how dangerous Reuniclus is, which doesn't necessarily mean much, but at least other mons can be played around even when one lacks designated checks or counters. If you want a more concrete example of the potency of Reuniclus, just check out the RUPL match between Feliburn and TDK, where Feli's Reuniclus ended up sweeping most of TDK's team even though he had a Sharpedo, a Zoroark, a Registeel, and a Reuniclus of his own. I think that game does a good job at showcasing how resilient Reuniclus is and how dangerous it is even when it blows its Z-move and when it accidentally has Psychic > Psyshock (lol).
I am of the opinion, and many others appear to share this opinion, that the meta is in bad shape at the moment, so having a few suspect tests might refresh the tier and make teambuilding less of an exercise that ends in "guess I'll throw the same 3-4 fat mons as usual on a team with a few offensive mons that complement them" since the more successful builds are starting to look dangerously similar. Reuniclus, of all mons that make the meta what it is today, is probably the most problematic of them all, so a suspect test is in order imo. Feel free to discuss if you guys feel the same way about Reuniclus and/or if there are other things that you feel warrant a suspect test somewhere down the line.