KratosMana I agree with your positions on diff rankings and such, but I do think that HP Ground and Passho Berry are decent options on Volcarona that you're kinda underrating. Dual STABs + HP Ground isn't even that bad of a set, although in many cases it is suboptimal. Replacing Bug Buzz is very viable if it's backed by Pursuit support to take care of the Latis (let's say you're using TTar + Exca for anti-hazard). Heatran alone is enough reason to run it because Volcarona is a fantastic lure for it, and it can be one of the largest obstacles to a Volcarona sweep. Passho Berry prevents Volcarona from being RK'd by CB Azumarill's Aqua Jet and has misc uses vs other Water-type attacks eg Scarf Keldeo if Volcarona isn't at full (a normal situation), setting up on Rotom-W with relative ease, setting up on bulky Water Scalds (Starmie and Slowbro are main examples). Considering that Water is a fairly dominant typing both offensively and defensively, Passho Berry makes sense as an option, of course depending on preference and the particular team.
I suppose I'll speak on the slate a bit.
Definitely agree with raising Empoleon. It simply has a ton of utility at the moment, as defensive sets check (although it doesn't always counter) a ton of threats like Clefable, Mega Diancie, Talonflame (w/ Defense investment), and Mega Aerodactyl and can provide invaluable SR/Defog support for balanced teams. Chople is a pretty underrated option that I talked with ben gay about a bit. It really enhances Empoleon's utility by allowing it to serve as a one-time check to tons of mons with Fighting STAB or Fighting coverage like Mega Lopunny, Megagross, Azumarill, Keldeo...it gives Empoleon more opportunities to get off a last ditch Defog/SR/Roar, which can prove insanely valuable. All in all a solid mon with tons of utility that belongs in B.
Skarm should definitely move up to A-. SpD sets have had a fantastic showing in particular recently, as they combine Skarm's renowned ability to deal with physical threats like Excadrill and Mega Metagross (although it does lose some capabilities in that aspect) with the ability to handle some key special threats in the current metagame like Mega Diancie, Latios, and Tornadus-T that lack Heat Wave, all very powerful and difficult to handle mons. This combined with Skarm's fantastic utility in its ability to provide SR, Spikes, and/or Defog support make it a solid contender for A-.
I haven't really done much testing with Mega Medicham or seen it in action much at all recently, but despite its lack of presence in the metagame I'd say it's still pretty good, and the advantages of Mega Gallade are overstated. Mega Medicham has two priority moves, which is extremely underrated in the sense that it gives Mega Medicham a nice option vs faster mons, and also utility in revenge killing as Mega Medicham's priority is surprisingly powerful. More immediate wallbreaking power is also significant. It is pretty useless against teams with Mega Sableye, but it does pretty well against most other teams, especially when backed by Pursuit support, as many teams simply aren't that well-equipped to handle it. I'd say B- makes sense.
Iffy on raising Starmie. On one hand, it's offensive set is up there with Excadrill in terms of being the best offensive spinner, sporting tons of offensive power and generally being difficult to wall with the coverage tools to catch most mons, even Ferrothorn if it wants to. The defensive set is a cornerstone on some balanced builds, as its spinning capabilities and ability to switch into the likes of Heatran and Keldeo consistently make it extremely viable and useful. On the other hand, it's a bit bizarre to place Starmie with Pokemon like Clefable and Mega Sableye, mons that define the tier to a far greater extent than Starmie. Starmie also has the issue that it's Pursuit bait, and defensive sets can even be setup fodder for mons like Mega Altaria, Clefable, and Mega Charizard X. Offensive sets are relatively unreliable in terms of hazard removal capabilities as they struggle to find switch-in opportunities and simply lack longevity, which is an issue regardless of how offensively biased the team is. I think A is a fine representation of Starmie's position in the metagame.
Don't have too much to say about Tyrantrum and Alakazam, just that I completely agree with raising them. Tyrantrum has insane destructive capabilities and actually some pretty neat versatility in terms of options between DD, Band, and Scarf. Alakazam's Life Orb set is a potent breaker that is difficult to handle for many balanced teams, especially seeing as Scarftar can't Pursuit it. Sash sets are also as good at RKing with the help of a guaranteed sash as ever.
