Aside from the Swords Dance set, does Skarmory really check/counter any of the other sets Aegislash carries? Only specially defensive Skarmory can really take a Shadow Ball as long as it has a +SpDef nature and Stealth Rock isnt up, but even then, if Aegislash is carrying Spooky Plate, its still a 2HKO:
252+ SpA Aegislash-Blade Shadow Ball vs. 252 HP / 252+ SpD Skarmory: 144-171 (43.1 - 51.1%) -- 57.8% chance to 2HKO after Stealth Rock and Leftovers recovery
252+ SpA Spooky Plate Aegislash-Blade Shadow Ball vs. 252 HP / 252+ SpD Skarmory: 172-204 (51.4 - 61%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
Skarmory seems like a shaky check/counter, if at all, unless there's something I'm missing that merits listing it under checks/counters (is the Swords Dance set even used anymore?)
Yeah it definitely is a shaky check/counter, especially since the SD set usually (or should usually) carries Head Smash, which OHKOes after SR at +2. Probably isn't worth listing.
On Speed EVs for Tank/SubToxic
Ok so...I definitely endorse the removal of the 12 Spe EVs. Usually you can't risk it against Tyranitar, and it's actually disadvantageous to have more Speed against Tyranitar, as it is able to take a Sacred Sword assuming physically defensive and KO with EQ in return. In this scenario, undercreeping is definitely best, even just for other Aegislash, but we won't mention this in the analysis. IMO 12 Spe EVs is a wasted and unwise investment, especially when they are less useful in the prescribed scenario for their use and Mega DD/Scarf so much more common/better.
Swords Dance
Head Smash: I think that Head Smash should be the first, and potentially only, slash on SD. A lot of the reason to run that set lies in Head Smash's utility of luring in and KOing Mandibuzz, Skarmory, Rotom-W, Landorus-T, and a number of other things that Head Smash just slaughters. Although it will typically result in a large health loss to Aegislash by nature, the ability to deal with these Pokemon is incredibly significant and makes it worthy of a primary if not solitary slash.
4 leftover EVs: It doesn't need the 4 EVs in SpD for Genesect anymore -- there is literally no reason to run them there.
Checks and Counters
Quagsire seems like an incredibly shaky way of handling Aegislash. Look at the Shadow Ball calc:
252+ SpA Aegislash-Blade Shadow Ball vs. 252 HP / 0 SpD Quagsire: 228-268 (57.8 - 68%) -- guaranteed 2HKO after Leftovers recovery
An easy 2HKO simply isn't acceptable from Aegislash's most spammed move for this to be called an even decent Aegislash check/counter. It can handle it in isolated 1v1 scenarios, but without any consistency in general it makes for a poor way to handle it overall.
---
This section should really have a section dedicated to Knock Off. Random Knock Offs from the likes of Thundurus, Mega Venusaur, Azumarill, Tornadus-T, etc. make for a large deterrent to Aegislash, posing a severe threat. This is a way a lot of Pokemon deal with Aegislash switch-ins.
Earthquake is also an extremely notable move, as it is the bread-and-butter physical attack used to bypass King's Shield. Earthquakes from the likes of Terrakion, (Mega) Tyranitar, and Mega Venusaur eliminate/drastically reduce the threat level of King's Shield to them and make Aegislash much easier to get around.
---
Add:
- SDef Dragonite as a good check to your typical Tank Aegislash
- Mega Gyarados as it can set up in standard Aegislash's face
- Bulky SD Mega Scizor is can set up on/threaten Aegislash offensively
- Umbreon as a good defensive check
- Landorus as a prime way of threatening it offensively (OHKOes with Sheer Force LO Earth Power)
- AV Conk which takes hits from it pretty and actually benefits from SubToxic's presence, at least to some extent, and can hit it with Knock Off
- Specs Keldeo isn't switching in easily, but can deal a lot of damage to it with its Specs-boosted Water STABs
- Mega Venusaur, especially SDef, can take Shadow Balls from it nicely and threaten in return with EQ/Knock Off/Sleep Powder, or even Leech Seed just to wear it down
- Specially defensive Rhyperior can tank any physical hits easily and tank Shadow Balls decently whilst posing a significant offensive threat in return (it can OHKO)
- Clefable which pretty much just sets up on Aegislash without a Steel-type attack/Toxic (which Magic Guard variants can avoid)
- Amoonguss which with SDef investment can easily take a hit and KO in return with Foul Play
- Tyranitar as posing a significant offensive threat if Aegislash is weakened (with EQ) and even pretty much walling it if physically defensive
- AV Slowking as it can take two Shadow Balls and easily KOes with Fire Blast
- Mega Blastoise as a spinner that poses a huge offensive threat with Mega Launcher-boosted Dark Pulse
- AV Azumarill with Knock Off, which is able to take the hits from SBall pretty easily and deal massive damage with Knock Off in return
- Mirror Coat Deoxys-D, which isn't really a check/counter in terms of switching in, but definitely puts a damper on it because Aegislash is otherwise a really good counterlead to it. If you're willing also mention Mirror Coat Alomomola :]
- Assault Vest Escavalier with Drill Run which can easily take SBall and KO back, and isn't phazed by Toxic
- Mega Absol as another offensive check
Offensive
- Air Balloon lets Aegislash spinblock Excadrill once, which is very useful for HO teams. Checking Ground-types once is very useful in general for HO teams
It isn't really 'once' if you play with it well. You can force out the Ground-type and keep Aegislash's Balloon intact through smart play. The emphasis on being a one-time check shouldn't be there.
Physical Thundurus should be mentioned as another offensive Defiant partner in addition to Bisharp.