I just want to make a full post explaining my reasoning for my opinions on how high viability should be formated.
S Rank:
Reserved for Pokemon who can sweep or wall significant portions of the metagame with little support, and Pokemon who can support other Pokemon with very little opportunity cost ("free turns"). Also the home of Pokemon who can easily perform multiple roles effectively, increasing their versatility and unpredictability. If the Pokemon in this rank have any flaws, those flaws are thoroughly mitigated by their substantial strengths.
This list contains four types of mons. Things that can sweep large portions of the metagame with VERY limited support, things that can wall most things in the tier, things that can support your team to an amazing level, and finally mons who are able to perform so many roles making it difficult to plan ahead and know who your counters are. All of these need to have their flaws by over whelmed by their significant advantages.
Gonna give example(s) of each:
Sweepers
Things that can sweep large portions of the metagame with VERY limited support
Feraligatr
These S ranked mons need to be able to do their role with little to no support. Gatr finds it's own opportunities which are numerous, and doesn't need help setting up. It rarely relies on its teamates since it doesn't need maximum hazard control, dual screens, specific targeting ect. Lum berry means it doesn't need heal bell.
Once it sets up it can break most of its counters in different ways. It's coverage helps it get passed the thngs that blockade it in the tier. (C ranked counter example is Raichu. Raichu lacks the coverage it needs to beat it's counters.) Gatr's ice punch and return allow it to beat the vast majority of NU viable stops to it's +2 water attacks.
Yes it has downsides but I will not get into them rn.
Walls
Things that can wall
most things in the tier without
having many downsides to
switching in
Hariyama
Mega-Steelix
If you notice the best walls in the tiers are not things that are simply hard to break (dusclops, seismitoad) but they also are very good at dealing damage. Steelix and hariyama both have high attack stats that make them somewhat difficult to switch into, prevent them from being set up fodder, and allow you to use them offensively if need be. Steelix even has the fact that very few things even beat it one vs one.
Bringing them in stops very high tier threats along with many low tier threats and switching in allows them to do a role you want whether it be setting up rocks, getting some status off, or picking off one mon they have to switch in
Obviously they have solid counters like pelipper for lix, or plume for yama, but they still are amazing mons.
I do not think hariyama should be S. I used it as an example of the type of mon but I feel A+ is good enough for it. If you want more explanation I will elaborate :}
Support Mons
Things that can support your team to an amazing level
Uxie
Combusken
Whether it is spike stacking, dual screens, rocks, or baton/wish passing this type of mon is able to make the rest of your team amazing. Uxie is an iffy example because it bleeds into both walls/unpredictables, and can even sweep with calm mind.
Uxie can support the team in so many ways multiple times. It can set weather, set rocks, heal bell, status, dual screens, and even get mementum though u-turn/memento. It can even run trick to beat things that want to try setting up. Uxie isn't there to take lives, it is there to help other mons like wall breakers/ sweepers.
Combusken is banned making it a great example :} It was able to easily bulk up and baton pass multiple times in a match to mons that had ways to get around moves like roar/yawn (xatu) there where things that could come in and force switches with something like d-tail which was not only over centralising, but allows combusken to attack and pass support on later.
Unpredictables
Mons who are able to perform so many roles making it difficult to plan ahead and know who your counters are
This type of mon can run so many different lethal sets, supportive sets, defensive sets you have no idea what they are going to do to beat you. The other catagories generally have some unpredictability but not nearly as much as these who can be doing many different roles and generally have amazing coverage. Mesprit is obviously a mon that can run anywhere from supportive options, set up options, wall breaking options, and coverage options.
What mesprit has is stealth rocks, trick scarf, great coverage, viable special and physical moveset, stats that are good no matter what it decides to run, and healing wish. Uxie obviously fits best in this catagory too.
Wallbreakers
Mega-Camerupt
Typhlosion
Wallbreakers would probabpy fit in best with the description of sweepers even though there are obviously huge differences.
I feel they need to be able to nuke the other team effectively, not need much support, and have ways to get around counters that doesn't require you to outpredict your opponent three or four times.
The reason I feel typh is not S material is because it needs support. It gets annihilated by hazards making you need to run lots of hazard control, it is very predictable since all good players tend to only run specs. Scarf is rare among top tier players because it simply doesn't work as well. In adition to hazard control it has to switch out against faster mons / priority furthering it's problems with hazards.
Not only that but typh has a select few mons that can really block its rampage. There are those mons with 4X weakness to hp grass who can switch in if not predicted (Rhydon + Seismitoad), ninetales+psychic cores, mantines (very viable rn), hariyama, and random others like lampant and regirock.
Typhlosion is by no means a bad mon XD. It is quite centralising since it in part forces you to run some antifire spam strat. However every person high ladder prepares for it so that's not an argument. Typh is good at doing damage but it is not on a level above the rest in my personal opinion.
Where Dentri stands
Typh --- A / A+
Camerupt --- A+ / S
Feraligatr --- S
Kangaskhan --- A-
Liligant --- A / A+
Uxie --- S
Mesprit --- S
Steelix --- S
Archeops --- A+
Hariyama --- A / A+