After playing this meta for a few weeks, peaking #1 a few times and experiencing a variety of different playstyles and unique strategies I have felt it is necessary to give my opinion on the current 'Mega Salamence + Item' suspect.
Not Broken. Firstly let me start by addressing the previous points stated by the opposition:
The first member of the opposition stated:
Firstly, I cannot see how you can compare the two metagames as they feature a completely different set of threats with different Pokemon rising in viability in this metagame due to their ability to compete with the Uber based mons. E.g. in Ubers, Mega Mawile is a C- ranked, whereas here it's one of the best, most dominant threats in the metagame. Stop comparing the two. Nothing makes me madder than when people compare Ubers and AG without accounting for the common occurrences of Mega Rayquaza and the lack of clauses. You're essentially doing the same thing here. Please stop.
Here we see AllJokesAside running the optimal Adamant DD Life Orb spread, assuming he can actually set up a Dragon Dance, he must rely on a Banded Mawile being locked into Sucker Punch? An ExtremeKiller Arceus that has been crippled to the point where a Stone Edge does zero to Mence? When are you planning on Dancing up? I do not see a chance for that to happen. I must say that sitting at 339 speed really isn't optimal with the omnipresent Lati formes, Diancie, Lucario, Timid/Jolly Arceus formes everywhere in the metagame. I find that you're just going to die to the faster threat regardless. In fact here are some calcs of my own I prepared that show how great that set is in the current metagame:
0 SpA Mega Diancie Moonblast vs. 0 HP / 0 SpD Mega Salamence: 338-398 (102.1 - 120.2%) -- guaranteed OHKO
+1 0 SpA Mega Latios Draco Meteor vs. 0 HP / 0 SpD Mega Salamence: 690-812 (208.4 - 245.3%) -- guaranteed OHKO
0 SpA Arceus-Ground Ice Beam vs. 0 HP / 0 SpD Mega Salamence: 332-392 (100.3 - 118.4%) -- guaranteed OHKO
4 SpA Pixie Plate Arceus-Fairy Judgment vs. 0 HP / 0 SpD Mega Salamence: 332-392 (100.3 - 118.4%) -- guaranteed OHKO
88 Atk Life Orb Mega Lucario Ice Punch vs. 0 HP / 0 Def Mega Salamence: 333-395 (100.6 - 119.3%) -- guaranteed OHKO (I'll give you that Ice Punch may be ran solely for this Dragon, but it works)
Whereas you are not going to get to +1 with that set, and in any given opportunity your opponent will just destroy the Mence easily.
The second member of the opposition stated:
No.
Haha, Flying is a great offensive typing and I wholeheartedly agree. What I find hilarious about this is there are a few areas you decided to allow the fully defensive factor of your calcs affect your opponent's attack, whereas they wouldn't need to be fully defensive because of outspeeding reasons. I do like how you acknowledged that many mons, that you state Mega Mence breaks easily, actually win in both a 1v1 situation or in general. Ice Punch MMX will always outspeed and OHKO. It isn't far from standard. You can't get up to +1 on any of these mons. AJA would rely on the fact that they're just going to switch when you send Mence in.
Abomasnow breaks you if you Dance unless you choose not to, Gallade Ice Punches and OHKOs while outspeeding your spread,
Heracross Rock Blasts on your Dance unless you choose not to,
Medicham wins if you Dance, Pinsir speed ties with your set,
Venusaur is irrelevant, Beedrill is relevant, there's one, Lopunny Fake Out + Ice Punch, Sceptile outspeeds and OHKOs, Blaziken runs Sash or Protect and OHKOs with Edge, Mewtwo OHKO with Ice Punch and outspeed, Skymin can hax. Can you please redo these calculations without the +1 boost, it's just silly. If you're playing with Beedrill, you have to ensure you don't get forced into a 1v1 with Mega Mence, otherwise +1 will never occur. This is an issue, I agree; but stuff like that is why it's one of the best mons in the metagame.
One could make the argument, that the opposing mons are only using Ice coverage moves to beat Mega Mence, but they're actually standard sets. Before you bring it up AJA, I got it covered dw.
I want you to test Mega Latios in comparison to this Pokemon. I would argue that at +1, Latios OHKOs more than what you've listed. The fact that Salamence can do it, while having issues in doing it isn't assuring to any Mence user.
Test Ho-Oh, Test PDon, Test EKiller, Test GeoXern. Please just don't think Mence is the only mon without a definite counter (Mence actually has reasonable answers)
252+ Atk Choice Band Mega Salamence Earthquake vs. 248 HP / 0 Def Arceus-Rock: 332-392 (74.9 - 88.4%) -- guaranteed 2HKO
252+ Atk Choice Band Mega Salamence Earthquake vs. 248 HP / 252 Def Arceus-Rock: 272-320 (61.3 - 72.2%) -- guaranteed 2HKO
In these calcs, Salamence is required to run a Choice Band and maximum Attack. It loses the speed tie to Rock Arceus in the prior calculation. It is then locked into Earthquake and can easily become set up bait by Lati formes and other Flying-type set up Pokémon, which seem to be prevalent in the Megamons metagame. Judgment without investment can pick up an OHKO.
These stats can again be applied to Steel Arceus and Electric Arceus, however they fail to OHKO back. Hence Rock Arceus is the best Pokémon. One may argue, that Rock Arceus would only be ran then to check Mega Salamence, however it is also able to OHKO Ho-Oh and resist all it's attacks, bar Earthquake which can do ~50% maximum. They can all OHKO Mega Salamence if given Ice Beam coverage.
252+ Atk Choice Band Aerilate Mega Salamence Double-Edge vs. 252 HP / 252+ Def Solrock: 182-214 (52.9 - 62.2%) -- 99.6% chance to 2HKO after Leftovers recovery
Solrock, an uncommon and somewhat gimmicky Pokémon can wall Mega Salamence's attacks and Will-O-Wisp Mega Salamence. If it chooses to Refresh, it is being ran on a non-Banded set, and hence will not pick up the 2HKO regardless.
However this if we're following the banning philosophy put in place by AllJokesAside and ScorrchingTheaph. That no Pokémon can wall all sets, we have disproved this. Now I go on to further my argument in saying, that I can name many Pokémon where this IS ACTUALLY the case. Name a Pokémon that walls Primal Groudon other than Ground Arceus? I struggle myself due to the immense capabilities of the Pokémon at question. Let's bring up a few calculations.
+2 252+ Atk Primal Groudon Precipice Blades vs. 252 HP / 200+ Def Arceus-Water: 363-427 (81.7 - 96.1%) -- guaranteed 2HKO
Where all Water Arceus can do back is fire off a weak Ice Beam or hope for ten misses in a row. In the other situation listed above, in any given 1v1 situation, the Rock Arceus would benefit. After one boost of the Mega Salamence, it can get up to the desired attack stat, so don't bring up the possibility of Dragon Dancing to appropriate levels.
252+ Atk Choice Band Aerilate Mega Salamence Double-Edge vs. 104 HP / 0 Def Primal Groudon: 301-355 (82 - 96.7%) -- guaranteed 2HKO
252+ Atk Choice Band Mega Salamence Earthquake vs. 104 HP / 0 Def Primal Groudon: 260-306 (70.8 - 83.3%) -- guaranteed 2HKO
That's literally offensive Groudon and it's still struggling to do anything effective! WOW! Now let's increase the bulk on that set. Here is standard Ubers support:
252+ Atk Choice Band Aerilate Mega Salamence Double-Edge vs. 252 HP / 56+ Def Primal Groudon: 264-312 (65.3 - 77.2%) -- guaranteed 2HKO
Full physical bulk.
252+ Atk Choice Band Aerilate Mega Salamence Double-Edge vs. 252 HP / 252+ Def Primal Groudon: 234-276 (57.9 - 68.3%) -- guaranteed 2HKO
And this is also going off the expectation that there are people who run Adamant Choice Band variants of Mega Salamence, which is most likely not the case due to the extra power being redundant if outsped by the Lati formes.
When are we banning PDon again?
You didn't list the counters.
No you're not, especially if you're not running max speed.
Its natural bulk is easily surpassed by many threats in the Megamons metagame due to the evident power creep. It is the same level of a threat, I agree. I only found a need to run one check for Mega Mence, heck I haven't even changed my team since the suspect and I'm still doing great. I think I appreciated your post the most as you acknowledged there are checks, whereas the others chose to skip the part where many Pokemon have this walling capability. There is one part that stood out for me though, is the Mega Rayquaza treatment you speak of. As an avid AG player, I find it disgusting that this is being compared to Mega Rayquaza. There isn't a single Pokemon in Anything Goes that walls every Mega Rayquaza set. Even Fairyceus gets 2HKO by certain Specs sets without being able to pick up the OHKO back. The meta had to adapt heavily to the presence of Mega Rayquaza, and I tend to have the thought that Fairy Arceus would be many ranks lower without its capability to check Mega Rayquaza. There are actually switch-ins to Mence here though, and they come in variety and they have not escalated in usage solely due to the presence of Mence but rather achieve a purpose + wall Mence. Rock Arceus is great for Ho-Oh, Charizards, Yveltal while obtaining Defog capabilities and winning against Lati formes. Skarmory walls the physical attacking sect of the metagame (bar a few mons due to typing and whatnot). E.g. It isn't 2HKOd by a +6 Arceus ExtremeSpeed. I find that rather than the metagame adjusting to Mence, Mence has adjusted to the metagame. The metagame is not threatened to the point that this needs to be banned.
I will continue with additional arguments in a separate post, as I doubt this will be enough to shake the bias from the Mence haters.