Built this tier a lot for WCoP, have a few things to say - will mostly just be focusing on my own nominations but I'll mention some others too.
S ranks should imo be:
S:
Landorus-Therian
Weavile
S-:
Heatran
-maybe some others like Clef/Koko/Ferro/Melm-
I don't think Lando has any business dropping like some previous posters have suggested but I do think Weavile deserves to go up one.
(moreso Urshifu but I feel it applies to both)
A -> A+
These two saw massive usage as a core. They pair phenomenally together; there really isn't much that can handle an Urshifu backed up by Future Sight, and while this has always been true, these teams have found more success lately by running Tapu Lele instead of a Slowtwin. Its Future Sight is ungodly strong, chunking physdef Slowbro for up to 50%, more than enough for Urshifu to pop it open. They also have really amazing offensive/defensive synergy; Urshifu smashes stuff like Heatran, Ferrothorn, Melmetal etc. while being an okay pivot into Weavile. Tapu Lele drops checks to Urshifu like Toxapex, Dragonite, Buzzwole etc. they're just a really good pair and I think they both deserve A+ at this time.
A- -> A
Blacephalon has seen a lot of usage in WCoP and is something I personally built a ton with to find structures I liked. For the most part, the only Ghost resist in this tier is Weavile; Tyranitar has been picking up a bit and is by far Blace's worst matchup, but you will very often run into a team that has no Shadow Ball resist and is forced to rely on very awkward pivoting to keep the clown in check. I think having two very good sets - Specs, which is one of the most brutal wallbreakers in OU, and Scarf, which devastates offense in similar ways to mons like Scarf Kartana - makes it a pretty versatile thing too, since if you see something like Blace + Kart or even Blace + Weavile at preview, you don't really know what set it's running. I find it's a bit difficult to build with since having next to no defensive utility is tough, and that Speed tier is just oh so frustrating - it's great but being just slower than Kartana is tragic. There are only so many routes you can take with it as a result. That said, it's a really strong Pokemon rn and I feel it's definitely on par with the likes of Zeraora and Volcarona.
A- -> A
Dragonite has a very valuable defensive profile atm, being a great check to stuff like Urshifu, Kartana, Heatran, Volcarona, Volcanion etc. and providing ever-valuable Heal Bell support. It fits phenomenally on those Koko/Ferro/Clef structures that saw a ton of use in WCoP and should rise a rank to reflect that in my opinion. Being so customisable is really great for it; if you need it to run moves to check any of Heatran, Kartana, Landorus, Glowking, Urshifu etc. it can do that thanks to that crazy movepool it has. Just think it's in a great spot.
A -> A-
Fraud Pokemon, just really hard to justify over Tapu Koko most of the time. Extremely minimal defensive utility and tends to fall flat in its sweeping role. Still pretty damn good for Pult-weak teams and smashes Sand like it's nobody's business but I think A- fits it better.
A- -> B+
High risk high reward breaker that's difficult to position and finds itself dying really quickly. Certainly an absolutely enormous threat, but doesn't feel like it's on the level of Volcanion or Victini at all. Too easily checked by stuff like Koko and Slowbro really; yes, they can't handle it long term, but it's not a long term Pokemon and will be dead long before it manages to break them.
B+ -> A
The immortal slug is really good rn even if it's a stupid momentum suck a lot of the time. Has a nasty habit of just 6-0ing teams; being a hard stop to Koko, Blacephalon (kinda), Dragapult, Zapdos etc. is just insane compression atm and it saw a looooooot of wcop usage because of that. Feels sorta par with Toxapex for that bulky water role, maybe a little worse but not enough to be a subrank lower imo.
B+ -> A-
Sand good, Drill's rlly hard to handle for a lot of teams with generally low Corv usage and SpDef Lando being far and away the most common variant, CB Tar is crazy tough to switch into, both should rise
Some other things that I don't feel qualified to flesh out but think they're worth nothing:
- Rain is good atm and should rise but other than Pelipper I don't know what should go up really
- Rillaboom's making somewhat of a resurgence and may be good enough for B+
- Rotom-W is getting crazy high usage and should rise but I don't feel like making an argument for it
- Victini could maaaaaybe rise altho idk how convinced I am. Really nice into a lot of trends like LeleShifu / FerroClef balance, though.
- Melmetal's lowkey broken.
Here's a quick 1am overall VR from me to end this off. Nothing is ordered within its subrank. I left out a lot of things because I don't really care too much about the low ranked stuff that I've never seen or used.