Update time:
Latios: A+ ---> S
Azumarill: S ---> A+
Thundurus: S ---> A+
Gengar: A ---> A+
Mega Gardevoir: A ---> A+
Mega Alakazam: A- ---> B+
Mega Aerodactyl: Stays in A-
Quagsire: B ---> B-
Hawlucha: B ---> B+
Cofagrigus: Unranked ---> D
Cobalion: Unranked ---> D
Mega Abomasnow: Stays unranked
Metagross: Unranked ---> D
Lanturn: D ---> C
Heracross: Unranked ---> D
Meloetta: Unranked ---> D
As usual, i will only talk about the Pokemon that weren't talked much or didn't reach a consensus as to where they should go.
Azumarill: That was a really hard decision, trust me. In order to measure Azumarill's viability as objectively as possible, we have to both compare it with the other S rank Pokemon and see how it fares against every playstyle, aka how consistently it performs. Regarding consistency, it depends on Azumarill's set. The Assault Vest set is great against offensive teams and has an incredible number of favorable matchups, but it's not that useful against balanced teams and basically useless against stall. The Choice Band set fares much better against balance, because it's able to break through defensive cores easier, but still struggles quite a lot with Pokemon such as Slowbro, Mega Venusaur, and Ferrothorn, all very common Pokemon on balanced teams. CB Azumarill is still good against offense, though it checks less Pokemon because of the worse bulk, but somewhat makes up for it with its revenge killing power, being able to OHKO Pokemon such as Excadrill and Landorus from full life or after SR, and not being set up bait for dangerous Pokemon such as bulky Mega Charizard X and physically defensive CM Clefable. The Belly Drum set is Azumarill's worse set, and even though it can be an effective late-game cleaner, takes away the greatest things about Azumarill: its typing and bulk. You have to save it until late-game if you want it to sweep, so that means that you usually forfeit Azumarill's defensive abilities. Belly Drum can do work against both offensive, defensive, and stall teams, provided its checks and counters are gone, but needs significant support for this to happen, as well as a free turn to safely set up, while being unable to offer any defensive synergy if it wants to sweep. Overall, Azumarill is pretty consistent, but not consistent enough in comparison to the other S rank threats, because it can struggle against any kind of team not named offense.
Now, let's start with the comparisons. Latios and Greninja work against any kind of team, i don't think anyone disagrees with this, so let's go to the less obvious S rank Pokemon. Specs Keldeo also does work against every single playstyle, because of Scald, which allows it to pressure most of its checks and counters, such as Mega Venusaur, Slowbro, Amoonguss, Latios, Latias, and Azumarill. Sometimes, Keldeo may need to take its time to wear down its checks and counters sufficiently, but it's worth it if it means it's able to break through the opponent's defensive core and basically carry your team. Of course Keldeo checks less Pokemon than Azumarill, but it more than makes up for it with its offensive presence and great Speed. As for Mega Charizard X, it has a combination of versatility and sweeping potential that Azumarill lacks. Jolly DD Zard X is a pain in the ass for offensive teams to face, who often rely on Pokemon such as Mega Manectric and Scarf Landorus-T as their revenge killers, with a few priority users here and there added to the mix. Jolly DD Zard X dgaf about any of this and can sweep entire offensive teams in a heartbeat if given the chance, which alone makes it a huge threat. Also, as a set up sweeper, Zard X has the benefit of being able to add defensive synergy thanks to its great typing, bulk, and Roost, as well as set up in a ton of Pokemon, even on offensive teams, such as Bisharp, Mega Scizor, Mega Manectric, Rotom-W, SR Clefable, Mew, etc. So, Mega Charizard X's sweeping potential alone is at least A+ rank worthy, if not S rank. Then, if you just add his versatility to the mix, namely its ability to run Bulky WoW, DD + 3 attacks, bulky DD + Roost, Roost + 3 attacks, and Tailwind + SD sets, it is not hard to see why it belongs in S rank, even though it has many important flaws. Azumarill just barely got kicked to A+ rank, and Pokemon such as Keldeo and Mega Charizard X are just slightly more effective in this metagame, so it's not like it's not on par with those Pokemon, and we already discussed that the line between S and A+ ranks is blurrier than ever, so i trust that you guys respect this opinion.
Mega Alakazam: Alakazam dropped because it provides zero defensive synergy, needs a turn to MEvolve which can be very hindering against rain offense, given how Mega Alakazam doesn't get many chances to MEvolve before getting in to revenge kill something, and is not that hard to play around thanks to the lack of spammable moves. For example, Mega Manectric, another effective cleaner, has way better early and mid-game presence thanks to Volt Switch + Intimidate, which makes it harder to play around, and more effective at wearing down its checks and counters.
Metagross: Pursuit + Earthquake is a really important combination that Jirachi lacks, as being able to pursuit trap Lati@s is great, as well as not being Bisharp and Heatran bait. Also, the added power helps keep up the offensive pace, and Bullet Punch is kinda nice too, at least for a D rank Pokemon.
Mega Abomasnow: Sorry, but unless i see this thing in action, i am not getting convinced. Even though it trust ben gay's judgment most of the time, i just can't see how a Pokemon so slow, with so many weaknesses, and without that good STABs (tons of checks and plenty of counters) either is worthy of getting ranked.
Meloetta: Great Gengar counter with an Assault Vest set, decent power and coverage. Tbh i haven't used this thing lately, but i trust ben's judgment on this one.
Changes to discuss:
Hippowdon: A- ---> B+
Tyranitar: A ---> A-
Bisharp: A ---> A+
Garchomp: A ---> A+
Garchomp (Mega): B ---> B-
Lucario: B- ---> B
Magnezone: A- ---> A
Gothitelle: B- ---> C+