It's about time we have another rank change now that stuff got banned. (Thanks to AM Vid for some of these) Sorry that it took so long :x
Stunfisk (Electric) D Rank -> C Rank
See All Fall Down's
post
Salamence (Dragon) A Rank -> B Rank
Although Moxie's fine and all, Salamence offer's nothing important to Dragon monos. Dragonite has Extreme Speed while Mega Altaria's just better in general.
Gliscor (Ground) B -> A
One thing Ground normally has trouble with is status and Toxic Orb Gliscor solves that while whittling down walls for Ground's sweepers
Snorlax (Normal) A -> B
After testing it, I've found Snorlax quite situational. Depending on its moveset it gets walled by certain things or it's setup bait when asleep. Normal's core is also more than enough to deal with Fire / Ice types.
Jellicent (Ghost) C -> B
Offers a nice Special wall that's immune to Scald and resistant to Lava Plume making it a nice partner to Mega Sableye who hates being burned.
Froslass (Ice) C -> B
One of Ice's few Fighting immunities / neutrals. Froslass has the added benefit of Spike stacking and bringing down one something threatening with Destiny Bond. Has access to a fast Taunt as well.
Scizor (Bug) S -> A
It's still an amazing mon, but I feel like it isn't that relevant anymore. Bug generally has no trouble against Fairy nor Rock and Scizor's still dead weight against certain types and Genesect outclasses it in various ways. (Genesect arguably has a better typed priority as well)
Conkeldurr (Fighting) A - > B
Conkeldurr just doesn't offer too much anymore. Fairies make its life miserable and its slow speed doesn't really help. Conk also ruins Fighting's momentum which is kinda bad.
Gengar (Poison) A -> S
Gengar's what prevents Poison from getting steamrolled by Psychic. It has multiple movesets so it's unpredictable.
Nidoking (Poison) A -> S
Gives Poison a much better matchup against various types such as Steel and Flying.
Mega Diancie (Rock) A -> S
No explanation needed. Just look at its speed, power and STABs :) (It gets Heal Bell too!)
Mega Scizor (Steel) A -> B
It doesn't really offer Steel anything aside from ensuring that 6-0 against Fairy. You're better off giving that teamslot to something like Doublade or Empoleon.
Quagsire (Water) A -> B
Unaware's cool, but it's not that good. Still weak to status etc etc etc, it's just not worthy of A rank.
Whimsicott (Grass) A -> B
It's not worthy of A Rank but it's still useful.
Alakazm (Psychic) A -> B
Psychic doesn't have enough moveslots for Alakazm, but if you're running HO it makes a decent revenge killer. (Although it's a little weak if you're using a Sash)
Mamoswine (Ice) A -> S
Its STABs can beat a ton of Ice's weakness and there are multiple movesets you can choose from.
Salamence (Dragon) A -> B
It doesn't deserve A Rank. Dragonite makes a better Dragon Dancer and Latias makes a better Defogger.
Azumarill (Fairy) A -> S
Makes a great wincon against many types and is a great Pokemon in general.
Klefki (Fairy) A -> S
Keeps Fairy together while providing utility in the form of Screens, T-wave, and Spikes. Has access to Foul Play so you can bop those SD Scizors :)
Cincinno (Normal) B -> D
It's not that good anymore, Normal users generally run Lopunny or Diggersby instead if they want a Normal attacker.
Toxicroak (Fighting) B -> C
Still weak to Psychic and it's hard to fit in. Not B Rank material
Hawlucha (Fighting) B -> A
No more Zapdos's walling it, no more Metagross's Bullet Punching it and no more Greninja's outspeeding it :D
Gyarados (Flying) B -> A
It got buffed when Zapdos was banned. Makes an amazing special tank or a Rest Talk Dragon Dancer. Neutrality to Ice is useful as well.
Aggron (Rock) B -> D
Tbh, unless if you're running a Trick Room team you're either running Mega Aggron or no Aggron at all. Besides, you have Tyrantrum now who is wayyy better.
Tyrantrum (Rock) Unranked -> B
A better Aggron with boosting moves :) Shame it's still weak to Ground and Fighting moves..
Yanmega (Bug) B -> C
It's interesting but it's 4x weak to rocks, and is weak to priority. Many Special walls can tank its moves and cripple it.
Aggron (Steel) B -> D
No one uses this, and is outclassed. It's super slow anyways so don't expect to kill a lot of stuff.
Manaphy (Water) B -> A
Underated and underused but really good if used right. Has access to Tail Glow for wallbreaking and Clam Mind + Hydration if you want to go a bulkier route.
Cradily (Grass) B -> A
Has access to Stealth Rock, Recover, decent Special Bulk and a neutrallity to Fire moves. Pretty nice mon in general.
Trevenant (Grass) B -> D
A lackluster Pokemon that offers nothing important aside from Will-o-Wisp.
Serperior (Grass) B -> A
Amazing Pokemon in general. Really fast, has a Nasty Plot nuke and is able to snipe stuff depending on what Hidden Power it uses.
Murkrow (Flying) C -> Unranked
Rip. Lets be honest here, no one uses this
Alololololololomola (Water) C -> A
A staple on Stall water and for good reason. Insane bulk combined with Wish and Regenerator keeps itself and its teammates healthy throughout a match.
Jellicent (Ghost) C -> B
Makes a great partner to Mega Sableye since it can take Lava Plumes and Scalds for it while wearing down its checks and counters with Scald
Uxie (Psychic) C -> B
Really good mon for HO Psychic. Arguably outclassed by Azelf but Uxie has the bulk, and is able to set rocks multiple times.
Lapras (Ice) D -> C
Its typing and special bulk lets it take Fire moves with ease and unlike Walrein it has a ton of support moves to abuse such as Perish Song and Heal Bell. If you want to use an AV it has enough moves for you do make a decent set.
Walrein (Ice) D -> C
Thick Fat lets it tank Fire moves like Lapras but it can run an AV since it lacks support moves.
Spiritomb (Dark) D -> C
Not as good as Sableye in many ways but it's a nice Calm Minder, and it has better bulk. Inflitrator's pretty cool as well.
If you want more of an explanation just tell me. I didn't feel like giving a very detailed explanation for every single one of these ;[