So i've noticed a few things about the meta. I'll try to subdivide this post into sections - as I feel it might make it that much easier to read and not as confusing.
The Underrated
While the latest edition of the Flying Press recently showcased it, I still firmly believe that reuniclus is one of the greatest balance and stall breakers in the meta, as well as one of the most slept on threats in the tier. Reuni as a breaker possesses an incredible matchup against most of the tier - with its most notable matchups being against bulkier builds. Most common balance builds - including my own - are quite weak to reuniclus, as most balance builds lack the means to break it, even before it has started to boost. The most "reliable" answers to Reuniclus being Ash Greninja, which cannot reliably remove it - prior to its transformation, it must risk being ohko'd by signal beam or focus blast if it doesn't achieve the flinch or the appropriate roll - and the other being Banded Tyranitar, which must risk a 50 / 50 in which it risks an OHKO from Focus Blast or Reuniclus freely switching. Against stall, Focus Blast variants can easily clean once sableye has been removed. Another often overlooked set on Reuniclus is the Psychium Z set, which allows it to reliably break past Quagsire and Clefable, while still possessing the utility of a breaker, though it does miss leftovers recovery, especially when switching into the likes of lucha and mmedi.
I've found that Greninja, Ferrothorn and Toxapex are the best partners for this mon - the former especially works well with it, as Greninja provides invaluable spikes support, whilst being able to check many 'mons on offence that have the capability to break through Reuni - namely SD Kart, Volc and Ttar. Reuni's capabilities of stallbreaking is incredibly helpful to Greninja, especially being able to remove Toxapex and Chansey. With the removal of the mentioned, Greninja is able to singlehandedly break stall. Ferrothorn and Toxapex essentially serve the same role, but with different additional benefits. Both act as a stop to greninja, relieving reuni of quite alot of pressure. Ferrothorn - similarly to greninja - also provides spikes support for reuni while pex provides tspikes or toxic support.
I don't know why people consider Gastrodon to be something that should only be used in tournaments, because it does soooo much work on the ladder. Being able to effectively shut down effectively invalidate a large amount of the meta (if i'm correct, it easily handles 44 give or take of the listed mons on the vr) without much effort, while completely invalidating an entire play style, which is currently at an all time high (iirc pelipper has close to 6% usage, feel free to correct me on this) and being quite splashable, there's little reason to use Gastrodon, especially on teams desperate for a compressed electric and water immunity. When compared to other bulky waters, it isn't as passive, especially when factoring in the special attack boost from storm drain, combined with Scald. Curse is also a solid pick in this meta, but isn't quite as effective as the standard set
- will finish post later
First of all thanks for the post lol, I used to really love posting in this thread but the meta is looking really stable right now, and it doesn't look like it will change before the next generation, unless Zeraora exceeds expectations and really shakes things up, of course no theorymonning, so we will have to wait.
I love Reuniclus, aside from it being a personal favourite of mine from design and the memories from BW, it is so slept on, even by me.
Magic Guard is a fantastic ability, especially on Calm Mind users which often are prone to getting worn down, particularly by Toxic, in addition hazards seem to be more rampant than ever thanks to Ferrothorn and Landorus and Greninja being dropped from Users.
Just to play devil's advocate, Reuniclus hates Knock Off, and the addition of Celesteela, Toxapex, the older mons like Heatran, Landorus, Ferrothorn and the nessecity of Choice Scarf users all heavily relying on their respective items means that Knock Off is everywhere, personally, I like to carry two users per team where I can. This is pretty easy seeing as Knock Off got a new Tutor is USM. Reuniclus also suffers a weakness to U-Turn, which is huge because it is slow and often can't hit your strong, slower U-Turn users and whatever you decide to do your opponent gets the momentum (that being said boosted Reuniclus is pretty hard to switch into). Also Assault vest users like Magearna and Tapu Bulu being really popular annoys Reuniclus, as even Psyshock struggles against them. Taunt is super annoying as without Recover and Calm Mind Reuniclus really struggles to do much of anything except act as set up fodder. Particularly against Heatran if unboosted, and lacking Focus Blast. Which leads me into my last point, dreaded 4MSS, without Calm Mind your bulk and attack will be lacking, without Recover you are prone to being worn down by U-Turn, without Focus Blast Steel-types are impossible to break, without Trick Room low speed means you're always relying on taking a hit before doing anything, which is a HUGE shame because it has such a deep move pool that could be taken advantage of.
As for Gastrodon, there is little bad I have to say, unfortunately Toxapex acts as direct competition, with far far better utility as a mixed wall thanks to its sky high defense and with Regenerator Pex is much easier to play and sustain, plus it is immune to Toxic. However, Gastrodon really forged a good niche, Storm Drain, Earthquake and an Electric immunity, role compressing a Koko check with a bulky water type and beating Heatran is amazing and it's a special wall that is criminally underprepped for, but of course, Bulu and Kartana exist.
Just to reiterate, I totally agree with you and I love both these Pokemon! I'm just playing devil's advocate to hopefully promote some discussion.