RESOURCE THREAD LETS GO
We're clearly at a pretty good starting point, but here are the changes I'd like to nominate.
S Rank should be split up. I know you're against this DEG but Char X is simply far better than Char Y in this meta. It has far more sets to run and simply beats more things, more reliably. Mega Gyarados is the single most important pokemon to build around right now, I don't think anyone disagrees that it's the best 1v1 pokemon overall. It should be ranked S+, Zard X should remain in S, and Zard Y should drop to S-.
Kyu-B should move to S- rank from A+. He's just as versatile (if not more so) as last generation, having viable sets in Scarf, Band, Specs, Haban Berry, Weakness Policy, and now Icium Z. He beats so many pokemon in the meta with his different sets, including but not limited to Gyarados (band), Charizard X and Y (Scarf), standard Porygon (Scarf), standard Crustle, Dragonite, Greninja, Mimikyu, Garchomp, and anything that relies on a defensive ability like Sturdy. Kyurem-Black is a force to be reckoned with this generation, and he absolutely defines the metagame.
Pory-Z should remain A+ Rank since he lost his best set (Custap) but still has options in Z-Conversion, Scarf, and Specs sets.
Magearna should move up a rank, from A to A+. It's basically the Mega Mawile of this generation, acting as a check for Gyarados and a counter for most Dragons and non-fire type special attackers. Of course, it's weak to fire and ground like Mawile is, but with a Specs boost or a Air Balloon type immunity, it's got the offensive firepower and defensive stats to take out a wide range of threats.
Dragonite should move down a rank, from A to A-. While extremely strong on paper, even a +1 Devastating Drake isn't going to damage all the fairy types wandering the tier, and Multiscale does nothing to stop Mold Breaker and Terravolt from ripping Dragonite apart. While Dnite excels low on the ladder, he runs into serious issues once people start using more and more of his checks, which all happen to be extremely good pokemon on their own. The last argument against Dragonite is that his coverage is generally very weak. Sure, DDrake hits hard, but Iron Head isn't even a guaranteed KO onto Tapu Lele, and Extremespeed is only good for cleaning up Sturdy pokemon. Earthquake and Fire Punch can do damage vs 4x weakness pokemon, but in general just aren't going to be used above DDrake. In this sense, Dragonite is a one-trick pony.
Metagross should move up to A ranking. He is extremely versatile, able to run bulky or fast, with move options in Meteor Mash, Bullet Punch, Zen Headbutt, Ice Punch, Thunder Punch, Earthquake, Grass Knot, and Substitute. He can EV to tank a +1 M-Gyarados Crunch and KO with two Thunder Punches, or he can EV to outspeed Zard and sub up on Flare Blitzes, Blast Burns, or Fire Blasts then fire off an Earthquake or Zen Headbutt to finish off his opponent. Metagross also performs very well against Sturdy pokemon thanks to his priority and fast frail attackers thanks to his natural bulk and amazing defensive steel typing.
Donphan's gotta go up. B+ is way too low for arguably the best user of Rockium Z and arguably the best Sturdy pokemon in the meta. In my eyes, he's on par with Crustle since both pokemon have many of the same checks and counters, but beat a lot of the same things. Crustle uses stat boosting to accomplish this whereas Donphan uses priority alongside his already powerful hits and his Counter/Endeavor. I don't think Crustle is too high, but Donphan should be at least moved up into the A rankings since these two pokemon are so nicely comparable and relatively equal.
Whimsicott and Jumpluff should NOT be so far apart. After the Prankster nerf, Jumpluff is as good if not better than Whims since while Whims can no longer threaten Dark types at all, Jumpluff is beating both Charizards, non-taunt Mega Gyara, Crustle, Donphan, non-scarf Kyu-B, Dragonite, Magearna, etc. If Jumpluff outspeeds you, it beats you (exceptions apply). If Whimsicott can tank a hit, it beats you (exceptions apply). Jumpluff outspeeds around the same number of threats as Whims can tank a hit from, therefore they should be ranked closer together, probably around B-.
That's all for now. I'll definitely contribute more later as we see changes start to come in.