A+ -> A
Primal Kyogre has been nominated to be placed in A+ rank a number of times, and in the last VR update, it was finally raised. One of the main reasons why a few users have nominated this Pokemon to be placed in such high rank is because of its reliable defensive counterplay being almost nonexistent; it is impossible to argue with the fact that Primal Kyogre is one of the most dreaded wallbreakers that every team must prepare for, but I do not believe its offensive prowess reserves a place in A+ rank. While Primal Kyogre is difficult to be useless against any team, at the same time, it struggles to net more than a few KOs in the practice. No matter how dangerous Primal Kyogre is especially when its moveset has not been identified, the omnipresence of Primal Groudon and Ferrothorn's increasing popularity continues to plague the full potential of this Pokemon. It is believed that running a maximized Speed investment is going to allow Primal Kyogre to further pressure Primal Groudon that directly switches in to remove Primordial Sea, but this became harder as many Primal Groudon variants started (or has been) running a fast variant; due to other possible pivots like Mega Salamence and Yveltal, it is entirely reasonable to say that Rock Tomb being common on SR / SR + SD Primal Groudon variants also contribute to reducing Primal Kyogre's attempt at offensively checking Primal Groudon. Primal Kyogre's potential is further limited by its lack of notable resistances and relatively low Speed, which can be worked on with full Speed investment but will result in its frailty against foes that Primal Kyogre will attempt to check (can switch into CM groundceus once, tomb + blades from pdon basically killing on switch).
Not to Primal Groudon's degree, but Ferrothorn also limits Primal Kyogre's usefulness significantly. It is the most commonly known that the relationship between Primal Kyogre and Ferrothorn is that the latter is a good pivot & check to former, but if we take this a bit further, Ferrothorn will proceed to use Primal Kyogre as fodder for entry hazards or Leech Seed. Unlike support Arceus formes, which are checked by Ferrothorn but can at least use utility options like Stealth Rock / Defog / Will-O-Wisp, Primal Kyogre mostly enters the field to solely attack; this means Primal Kyogre will more likely going to give Ferrothorn a free turn and essentially do no positive to its teammates other than leaving a minor chip on it. Aside from Pokemon like Ho-Oh, Ferrothorn's other offensive checks will have to lose 12%, potentially 24% of their health just because Primal Kyogre has entered the field... or they will have to deal with Spikes. In order to avoid this, Primal Kyogre will essentially have to use itself as a fodder for double switches unless it runs Water Spout, which... still has to predict around Primal Groudon and other water-resistant pivots and is plagued by a minor chip.
As long as the Pokemon that contributes the most to limiting Primal Kyogre's full potential, and as long as the Pokemon that can punish Primal Kyogre's entrance to the field with Leech Seed or Spikes, I won't see Primal Kyogre's usefulness hitting the similar level of the Pokemon currently listed in A+.
A- -> A
Ferrothorn is mostly known as one of the rare Spikes setters that can fit into balance teams while providing its team with a check to Primal Kyogre, support Arceus formes, and a few Toxic users. Many Steel-types, especially those whose viability sizeably rely on their access to entry hazards, have fundemental issues of being passive in Ubers's standards and having a one-dimensional way to punish prominent checks like Primal Groudon. Ferrothorn is completely set apart from this category due to its access to Spikes which causes a predictable move from an opponent trying to quickly send their Defog user, and Leech Seed that makes it impossible for a foe to directly switch into and set up on Ferrothorn. Leech Seed is also a key factor that makes Pokemon like Primal Groudon hesitate before switching in due to it reducing the net damage a pivot will take from Primal Groudon and essentially taking off 1/4 of the health just because of switching into Ferrothorn. This is significantly more notable than other Steel-types that throw Toxic, run away, and hope one of its teammates won't get overly chipped.
Aside from those, Spikes continue to benefit a countless number of balance builds and checking Primal Kyogre remains important as Primal Groudon is inclining more on running offensive sets. This Pokemon with massive and near exclusive utility could be placed higher than Pokemon in A rank.
A- -> Somewhere higher within the rank
I once nominated Arceus-Fairy to be dropped out of the domain of letter A, but this time, I would have to propose its rise. I previously criticized Arceus-Fairy's incapability to punish Primal Groudon and Necrozma-DM, but an increased number of offensive variants of Primal Groudon made it a little shakier pivot to Arceus-Fairy, which takes a large chunk with entry hazards - a similar damage output when compared with Magearna's Fleur Cannon, which Primal Groudon should think twice before switching in. While a poor matchup against Necrozma-DM continues to be a pain for Arceus-Fairy, its utility of checking Yveltal and Marshadow and having a solid recovery makes this quite forgivable. Mentioned two Pokemon are also common countermeasures to prominent Necrozma-DM & Ultra Necrozma, so this also gives Arceus-Fairy a better chance to perform against more teams. I believe this Pokemon is honestly better than Arceus-Dark, but I won't propose A just yet.
B -> B+
This Pokemon is not commonly seen, but its potential is largely underappreciated. Many users avoid using this Pokemon because it ends up being another passive Steel-type that does not provide the team with security against Xerneas or support Arceus formes, but there are also other massive utility options that are ignored. Skarmory is arguably one of the only Pokemon that can switch into Necrozma-DM and won't be annihilated when Necrozma-DM Ultra Bursts. Against Ultra Necrozma, making a wrong prediction by sending in Pokemon like Primal Groudon, Yveltal, and an appropriate support Arceus, giving a free Swords Dance, losing a Pokemon, and having to send in something to deal with a +2 Ultra Necrozma can have a significant impact in games, but Skarmory can avoid this concern, being a good insurance to Necrozma-DM and Ultra Necrozma except when it is facing less common CM variant. Skarmory is also one of the limited answers to EdgeQuake Primal Groudon that can't be brought down simply by using common support Arceus forme or Mega Salamence. Being a Spikes user (which is great bc I stated earlier) and being immune to Toxic means that there are plenty of opportunities for Skarmory to switch into something it walls (DM / Ekiller / Groundceus / Waterceus w/o Judgment) and spam Spikes. One more minor thing, Sturdy + Whirlwind can be "one free mistake" in an emergency and this may actually save some games from ending up in a jank way.
Lastly, I believe
should rise with Sticky Webs becoming more common and Mega Scizor can be worth talking about.