Since I don't feel like enough people have really discussed it, I'd like to go ahead and talk about
Terrakion
I think that for the time being, Terrakion should be put in A, since there are a few things that for me, are enough to keep it out of A+ right now. Terrakion's most potent set is currently its Double Dance + Rockium Z set, as with a boosted Continental Crush, Terrakion can easily break past things like Alo, Suicune, Amoonguss, Slowbro, and bulky Celebi, which can otherwise tank a hit quite comfortably and KO it or cripple it. Due to its ability to break past a lot of traditional switch-ins, Terrakion obviously has a place in the meta with this set and can be almost unstoppable when set up. However, I feel like both setting up and removing various threats are two large enough of concerns for Terrakion to justify, for now, ranking it alongside the likes of Primarina and Raikou. As far as setting up goes, Terrakion can at times find itself at a loss as to whether it should set up Rock Polish or Swords Dance. Swords Dance is the no-brainer against defensive teams, but Rock Polish should probably be set up first against more offensively inclined teams so Terrakion can outspeed all of its opponents. However, against offense it often isn't able to reliably set up with both Rock Polish and Swords Dance due to its really poor defensive typing, while that isn't a struggle with a similar sweeper in Cobalion. Upon setting up, Terrakion still has to make sure that there are a few more Pokemon that are removed before it sweeps. Scizor is omnipresent in this meta, and due to Bullet Punch, requires removal. Crawdaunt and Nidoking are becoming increasingly more viable and prevalent, and also need to be removed, as Crawdaunt revenges with Aqua Jet while Nidoking resists Terrakion's STABs and KOs in return with Earth Power. There's also the tier's plethora of defensive Steels that are becoming more important to include on teams, like Bronzong, Doublade, Forretress, and Klefki. This can at times restrict teambuilding to Pokemon that can reliably take care of these threats, like the situational Magneton, or Stealth Rock-weak Fire-types, or Psychic-types that are weak to the ever so prevalent Pursuit, which as said before, isn't a struggle suffered by Cobalion. Overall, Terrakion is a devastatingly powerful threat once set up, but just needs to be more carefully built around than Cobalion, has a less convenient defensive typing for setup, and slightly restricts teambuilding a bit more. The payoff is of course absolutely amazing, which is why I'm proposing for placement just below Cobalion, but for now I think that Terrakion fits comfortably in the subrank below its Steel-type brother.
While I'm here, I'd also like to propose that a few changes within the C rankings happen, as at the moment I feel like there are a few things between C+ and C- that could either rise or drop. I know this post has been long, so please bear with me, but here's what I think should happen:
Tsareena should move up to B-: I was honestly really disappointed in seeing Tsareena drop two entire subranks, since it really deserves better than that. I felt as though my last post regarding Tsareena was quite sufficient in terms of stating why exactly Tsareena deserves at least B-, and the information I used then is still valid now. Tsareena has plenty of perks over its competition in Tentacruel and Forretress to justify use. Reliable recovery in the form of Synthesis allows Tsareena to sustain itself and consistently spin throughout a match, whereas Forry and Tentacruel must either risk being worn down over time or seek support from Wish users, which both restricts teambuilding and can at times stack weaknesses. Trop Kick and Aromatherapy are also really useful options, as together they allow Tsareena to really reliably 1v1 a lot of common hazard setters that otherwise win against Tentacruel or Forry, like Hippowdon, Gliscor, Swampert, and Krookodile, which all hate the attack drops Trop Kick burdens them with. Overall, Tsareena has too many uses of its own to be ranked under Forretress, and should instead be ranked alongside it, as both are about as consistently useful as spinners.
Metagross up to B-: Up until now, Metagross has been somewhat mediocre. However, the newfound viability of its Assault Vest set has honestly done this thing wonders in matching up well against a ton of huge metagame threats, as well as even being put to good use in UUPL. Latias, Clefable, Primarina, Keldeo, Celebi, Starmie, and Swellow are all really potent special attackers right now that are more or less stopped dead in their tracks by Metagross, and the dual utility of checking these threats, Pursuit trapping, and offering an amazing offensive presence is enough for me to believe that right now, Metagross has much more of a consistent and appreciated niche than its C+ brethren in Lucario, Arcanine, and Cresselia.
Crobat up to B-: Yet again, we see a Pokemon in C+ that should very well rise out of it. Crobat's an extremely useful Pokemon in the current metagame in that its Speed tier is beyond useful for checking things like Infernape, Celebi, Krookodile, Keldeo, and more. Alongside being able to check these threats, the utility of infiltrator Toxic/Taunt, an extremely fast U-turn for generating momentum and chipping foes, and even Defog overall turns Crobat into a Pokemon extremely capable of supporting several archetypes, ranging from hyper to bulky offense, which is enough for me to believe that it's currently got the stuff to be in B-.
Salazzle and Tornadus up to C+: Posts regarding the ranks of these two Pokemon have been made and each received quite a bit of support, and I'm still a little perplexed as to why such potent threats reside in C when both Salazzle and Tornadus are too consistent in this meta for that rank. As I said in an earlier post, Salazzle sits in an amazing Speed tier, which in terms of wallbreaking early-game, makes it a better choice than Infernape since its checks are very limited between Dragon Pulse and Hidden Power Grass as its opted coverage. It also can at times score easier setup opportunities against things like Togekiss, Clefable, choice-locked Primarina, and Fighting-types due to its really unique typing. As for Tornadus, it's just a really amazing role compression mon in that it can plow holes through its opponents teams with its nigh unresisted coverage, while also supporting its teammates when weakened with a priority Tailwind, which is extremely useful considering the prevalence of Pokemon that'd appreciate doubled Speed, like Primarina, Mega Blastoise, Volcanion, Krookodile, etc. Overall, both of these Pokemon have too valuable of niches to justify staying as low as C any longer, and are also just simply better than what's currently in their rank.
Bruxish up to C: Nothing's necessarily changed for Bruxish since it was first ranked, but I genuinely feel that it thrives much more in the metagame than anything else in C-. Its Swords Dance set struggles against extremely offensive teams and the ever present Bisharp, but can do wonders against stall, balance, and bulky offense. Psychic Fangs is an amazing nuke that plows through any unresisted targets, and since Dark- and Steel-types are generally fairly easy to remove with the support of Fighters and Psychics are nailed by Crunch, it doesn't take much for Bruxish to begin posing a major threat late-game, even despite its competition with a similar Pokemon in Mega Sharpedo.
Thanks for reading! I also wanted to voice support for a Necrozma drop, a Quagsire rise, and a Venomoth rise, but feel as though nominations regarding these changes have been really thorough and by themselves justify changes in the ranks of these Pokemon. I hope you guys agree with what you read, and sorry that this was so long!