I think it's nice that you've put a lot of effort here AHappyCactus but there are actually a lot things I consider outright wrong here or they just aren't recent additions to the meta game.Absolutely agree with mega medicham to A-. In fact I would not be surprised if it were nominated to be A. Here's the metagame shifts that I think justify this raise.
The Decline of Mew.
- About a month or two ago when PhysDef mew was on so many teams, it was seriously difficult to use mega medicham. Since that point, there have been two significant changes surrounding mew. The first is that it has simply dropped in usage a considerable amount. As always, the metagame adapts and mons like Ash Gren, Fairium-Z Mag, Bug Buzz Volcarona, Darkinium-Z Kartana, and plenty more began to spring up. Plus, other defoggers began to see more usage so the competition was pretty high from stuff like Mantine, Scarf Lati, Mega Sciz, Zapdos, Etc. So that's my long-winded way of saying: Mew is less common now.
- A second adaptation we've made is the really cool Koko + Medi core. This makes thunder punch do obscene amounts of damage. Most mews are running speedier sets, outspeeding stuff like jolly zygarde. Medicham abuses this because this mew does not run enough speed to outspeed you, but it is still sacrificing that extra bulk for the speed. This less-bulky mew does get 2HKO'd most of the time from T-punch after rocks (Which it will usually come in on, considering it's the defogger of the team)
252 Atk Pure Power Medicham-Mega Thunder Punch vs. 240 HP / 156 Def Mew in Electric Terrain: 175-207 (43.6 - 51.6%) -- 68.8% chance to 2HKO after Stealth Rock and Leftovers recoveryTapu Koko Core
- I cannot stress the synergy between these two. Think of the most common koko switch-ins. Ferrothorn, AV Magearna, SpDef Tran, Chansey, AV Magnezone, Tangrowth, Mega Venusaur, etc. Koko Volt switches (Or U-turns) on every single one of these threats, and Mega medicham can come in and pick up a kill for free.
- Another thing Medicham benefits from koko is electric-terrain boosted T-punches which I mentioned earlier. Mew is not the only thing it can muscle past. Other mons include Mega-Sableye (Not that stall exists anymore lol), Celesteela (Removes the would-be 50/50s with protect as well as simply doing more damage than HJK), Clefable, and a few more mons that medi can beat with thunder punch like mantine and fini.
Existence of CelePex
Anyways, needless to say I think Mega Medi is more than deserving of A- at the very least. It absolutely is better than the likes of skarm or weavile, and is on par (If not better than) many A- mons like zapdos, Mega Sab, Pelipper, and Mega Lop.
- Medicham, especially when paired with Koko, absolutely disassembles this core. We talk about how important it is for a breaker to be able to bust past this core, and none do it better than Mega Medicham.
- In fact, bulky teams as a whole really are common nowadays. Slower fat teams in general are everywhere, and with CelePex at the core, medicham can bust past them easily. Other aforementioned mons that have been seeing more play include Mega-Venu and Mantine among others that I won't bore you guys in repeating.
For one Mew hasn't dropped in usage the past two months it's actually got MORE popular. For the month of august Mew had a usage of 10.26575% in ou above 1825 and in September it had a usage of 11.42156% in the same category. Mew hasn't exactly fallen out of favour much in tournaments either it's still liberally used on tons of balance teams. Similarly Clefable is decidedly more popular at the moment and that's a fair check to jolly Medicham anyway. Unless you are running adamant on your Medis which has it's own issues like being slower than tons of important stuff in the tier like offensive Lando and Tapu Lele.
Tapu koko + Medicham is something we've had literally since Medicham was released. It was actually extremely popular upon release. This isn't new at all and shouldn't cement a raise on the VR for it now. It's also a lot more prediction reliant than you were letting on. Back when Dugtrio was around it was more important but it's still relevant now. It's basically a 50/50 between your opponent going to their ground type to eat the t-punch or staying in to wisp/recover and electric terrain is somewhat short lived. It's also an extremely telegraphed play. If your Koko immediately pivots out into Medicham and they have a solid Medi switch in like Mew most decent players are going to be smart enough to realise that you are running t-punch.
Celesteela Toxapex balance is again not a new thing. This is literally months old and also guess what. These teams do actually run Mew and Clefable a lot of the time. Neither Celesteela nor Toxapex are able to deal with Zygarde so if they aren't using Lando or Bulu something like Mew or Clefable is actually a likely partner on these teams. That goes double because they can also defog/setup rocks which is something Celesteela and Toxapex cannot do and again these CelePex users are conscious of Medicham and might decide to use Clefable or Mew just to deal with it. Mew actually appreciates having Toxapex on the same team because it absorbs T Spikes for it so again these are common partners.
I'm not saying Medicham shouldn't rise but I don't find these arguments compelling at all. Furthermore i struggle to see many reasons to use Medicham over something like 3 attacks roost Charizard X or Mega Pinsir. It's main advantage is not being rocks weak but I don't think that's huge enough to say it's marginally better than those two when they are better at breaking teams open. If Medicham ends up rising I would at least hope to see Charizard X rise as well.