S Rank:
Pokemon in this rank fill all of the main criteria and then some with a strong proficiency in one or more of the positive traits. If a Pokemon in this rank has any downsides, they are usually tame or eclipsed by their obvious assets.
S

Incineroar

Passimian

Slowking
A Rank:
Pokemon in this rank may fill the majority or all of the positive criteria. These Pokemon may have one major or a handful of minor negative characteristics that could set them back.
A+

Aerodactyl

Heliolisk

Steelix

Weezing

Rhydon
A

Dhelmise

Garbodor

Comfey

Rotom

Pangoro

Druddigon

Vaporeon

Xatu
A-

Sigilyph

Delphox

Whimsicott

Seismitoad

Blastoise

Sceptile

Togedemaru

Magmortar
B Rank:
Pokemon in this rank do an alright job fulfilling criteria, albeit not as convincingly. These Pokemon will have some issues you should be accounting for while building your team.
B+

Vikavolt

Sneasel

Guzzlord

Alolan Exeggutor

Palossand

Scrafty
B

Golbat

Vivillon

Braviary

Absol

Decidueye

Mega Glalie
B-

Samurott

Accelgor

Medicham

Gallade

Mega Abomasnow

Ferroseed
C Rank:
Pokemon in this rank do a mediocre job at filling criteria. The sizable amount of negative characteristics associated with these Pokemon are something to weigh against their positives before you fit one on a team.
C+

Silvally-Steel

Charizard

Clawitzer

Victreebel

Mega Audino
C

Mismagius

Piloswine

Aurorus

Malamar

Pyukumuku
D Rank:
Pokemon in this rank are those that are NU by usage, but are otherwise unviable. Do not discuss the placement of Pokemon here nor nominate Pokemon to move up/down to this rank.

Ambipom

Hariyama

Hitmonlee

Hitmontop

Klinklang

Mesprit

Miltank

Minior

Typhlosion
So, there isn't really a particular metric I went with when making this; I more or less just went with the stuff the normal VR goes with.
I don't think I had any particularly notable changes; I unranked/D ranked a shit ton of Pokemon (Regirock, Torterra, Mesprit, Hariyama, Silvally-Poison, Clefairy) that in my opinion lack enough of a niche to be ranked. Sure, these are usable Pokemon; however, I think there's generally not much reason to use them over more consistent options unless your team simply needs the very select tools they can provide.
My S and A+ ranks are rather different from the current VR. Like in the most recent voting slate, I do have Slowking in S, but I also have Aerodactyl above Heliolisk within A+. From my experience, it is incredibly difficult to have a game in which Aerodactyl will be deadweight or struggle to contribute; at the worst, it'll Pursuit trap something, switch into Incineroar a couple times, or chip away at something like Steelix. On the other hand, Heliolisk can really struggle against certain builds like Seismitoad + Rotom that make predicting super necessary. Of course, Heliolisk is one of the most terrifying wallbreakers in the tier, so I was unwilling to drop it out of my top 5, but I think Aerodactyl generally has more favorable matchups than Heliolisk does.
Garbodor dropped from A+ to A mostly because of competition from Weezing defensively. Garbodor has much better offensive potential sure, but it ends up struggling at times defensive because of its lack of a Ground immunity, which can leave it suffering against Pokemon like Passimian, Comfey, and Earthquake Sceptile.
Togedemaru is in mid A- rank for me mainly because of role compression. I think Togedemaru sucks overall as a Pokemon, but it does enough jobs at an average level to warrant inclusion on a lot of teams. Similarly, Blastoise is in mid A- because of meh role compression, but it suffers a lot currently due to Ice Beam vs Toxic being a bit more troubling. People also seem to in general be shifting away from Blastoise + Weezing builds, which doesn't help its case.
I put Sneasel at the top of B+ because it just struggles to contribute much of anything. Sure, you can cripple Incineroar by removing its Berry, but what are you doing afterwards...? Sneasel is just such a magnet for metagame staples that bend it over that it just doesn't have a large impact on games anymore. Aerodactyl largely outclasses it as a Pursuit trapper because of its defensive utility letting it come in more often, and both it and Absol have the sheer power Sneasel at times lacks. It's still good, but it's nowhere near its peak.
I ranked Victreebel because of its tour success. It's obviously no Vileplume, but it has some decent defensive utility with its typing and Strength Sap.
Piloswine is bad. Never once do I teambuild and think "wow, Piloswine is the Stealth Rock setter for this team!". It's worse than Rhydon in essentially every way outside of lacking a 4x weakness to Water and Grass.
That's about it really. I've enjoyed this generation a fair bit and have come around to appreciate the current metagame a fair bit. While it still has super standard builds floating around, I feel there's enough room for viable innovation, which makes it much more pleasurable to play and teambuild in. Hope to see y'all around for Generation 8.