Hey! It's nice to see another Volcanion team at this point in time, since it's seemed to lose a lot of the hype it had at the time of its release.
What strikes out immediately to me is the fact that you have offense in the form of Volcanion + Scizor with some pivots (Landorus-Therian and Rotom-Wash), but you added on two very passive and defensive pokemon being Mega Sableye and Empoleon. Since this looks to be a bulky offense team, having some pokemon with defensive capabilities is fine, but I think that these two pokemon are far too passive to have any merit on an offensive team. The fact that they're so passive means that they're going to sap up a lot of momentum, which is what offensive teams utilize to maintain the upper-hand against other teams. This is a big problem for offensive teams because it gives opposing teams free switch-ins to certain wallbreakers/stallbreakers that completely wall either Mega Sableye or Empoleon. The team does have defensive pivots in the form of defensive Landorus-Therian and Rotom-Wash, so switching into powerful pokemon isn't extremely difficult or impossible, but Mega Sableye and Empoleon do invite in specific breakers that the team is completely overpowered by, namely Mega Charizard Y and Specs Keldeo in the case of Mega Sableye, and Serperior in the case of Empoleon. Additionally, the team lacks a stallbreaker which, coupled with the fact that you have two very passive pokemon on the team, means that the team is going to have a pretty difficult time in a matchup against stall.
You mentioned that you wanted a specially defensive defogger when you chose to use Empoleon on your team and that you'd be open to replacing it if there was a better option. Fortunately, I've found a better option that fits the criteria you outlined. That option would be Latias.
Latias @ Life Orb
Ability: Levitate
EVs: 72 HP / 184 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Draco Meteor
- Psyshock
- Defog
- Healing Wish
Latias, while not as specially defensive as Empoleon, is another specially bulky pokemon. Latias and Empoleon may check different things, but Latias is able to check certain pokemon; such as Keldeo, Mega Charizard Y, and Thundurus; that are problematic for the team, whereas Empoleon can't check any of those. While not very relevant to the reason Empoleon was changed, Latias' Healing Wish can be very beneficial since there are a few pokemon on the team that can potentially sweep late-game and being able to remove a status infliction or heal them up to full health at that point in the game could possibly guarantee the win.
As I mentioned earlier, the team needs a way to muscle past stall teams. Mega Sableye should pretty much only be used on stall and semi-stall teams. The role that it has on those types of teams is unnecessary for bulky offense teams such as this one. Because of this, I'm going to change Mega Sableye to something that's still defensive, but has offensive capabilities unlike Mega Sableye. The team still needs an answer to Serperior, so to add a counter to Serperior as well as a stallbreaker, I suggest replacing Mega Sableye with stallbreaker Togekiss.
Togekiss @ Leftovers
Ability: Serene Grace
EVs: 252 HP / 80 Def / 176 Spe
Timid Nature
IVs: 0 Atk
- Nasty Plot
- Air Slash
- Heal Bell
- Roost
Togekiss is an interesting stallbreaker that isn't very common in the OU metagame. I picked this mainly because it was the only stallbreaker that could reliably take on Serperior that wasn't a fire type. The combination of Volcanion + Togekiss can take on a lot of popular cores and pokemon used on stall teams. 80 Def EVs are used to be able to survive 2 Psyshocks from Latios as well as two Returns from Mega Lopunny after Leftovers recovery.
I actually made this change before I added Togekiss, but after I removed Mega Sableye, the team was looking pretty pressured by Bisharp and Gengar. I figured that an easy way to remedy this problem, since the mega pokemon on the team was removed, was to make Scizor the mega for the team.
Scizor @ Scizorite
Ability: Light Metal
EVs: 248 HP / 44 Atk / 16 Def / 200 SpD
Impish Nature
- Swords Dance
- Bullet Punch
- Knock Off
- Roost
Having Mega Scizor over CB Scizor means that Bisharp and Gengar are handled more easily due to the increase in bulk and the fact that Mega Scizor's item isn't able to be removed, meaning that Bisharp's Knock Off damage is halved.
For the final changes, replace the 8 SpD EVs on Rotom-Wash with 8 Spe EVs. 8 Spe EVs allows Rotom-Wash to outspeed Adamant Crawdaunt. Also, make Landorus-Therian's Speed IV 31 and change the spread to 248 HP / 244 Def / 8 SpD / 8 Spe and change its item to Rocky Helmet. I don't know what you needed to lower the speed for. Possibly to be slower than something for slow U-Turns, but I'm not sure which pokemon that could be. In any case, this spread is the standard defensive spread. The 8 speed EVs allows it to outspeed 219 Speed Rotom-Wash, 248 HP EVs puts it at an odd HP number (which is better since I took off Leftovers) to lower Stealth Rock damage, and Rocky Helmet over Leftovers because it allows for pokemon to be weakened over the course of a match due to Rocky Helmet damage which makes sweeping with something easier.
I hope that these changes help you out in the future. Unfortunately, I couldn't find a way to keep the Pursuit + Volcanion core for the team. It's a great core since it eliminates the Lati twins which are the main answers that people have for Volcanion, but I had to have Knock Off on Mega Scizor since removing Mega Sableye took off the only Knock Off user for the team. If I were to keep Pursuit over Knock Off or replace Scizor with a different pursuit trapper, I'd probably have to change the team around too much to be able to make the team as good as I can. Anyway, good luck with the team!
Summary of Changes:
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8 SpD EV --> 8 Spe EV
Change spread
Importable:
Landorus-Therian @ Rocky Helmet
Ability: Intimidate
EVs: 248 HP / 244 Def / 8 SpD / 8 Spe
Impish Nature
- Stealth Rock
- Earthquake
- Stone Edge
- U-turn
Rotom-Wash @ Leftovers
Ability: Levitate
EVs: 248 HP / 252 Def / 8 Spe
Bold Nature
IVs: 0 Atk
- Hydro Pump
- Will-O-Wisp
- Volt Switch
- Pain Split
Latias @ Life Orb
Ability: Levitate
EVs: 72 HP / 184 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Draco Meteor
- Psyshock
- Defog
- Healing Wish
Scizor (M) @ Scizorite
Ability: Light Metal
EVs: 248 HP / 44 Atk / 16 Def / 200 SpD
Impish Nature
- Swords Dance
- Bullet Punch
- Knock Off
- Roost
Volcanion @ Choice Specs
Ability: Water Absorb
EVs: 4 HP / 252 SpA / 252 Spe
Modest Nature
IVs: 0 Atk / 30 SpA
- Steam Eruption
- Flamethrower
- Sludge Bomb
- Hidden Power [Grass]
Togekiss (M) @ Leftovers
Ability: Serene Grace
EVs: 252 HP / 80 Def / 176 Spe
Timid Nature
IVs: 0 Atk
- Nasty Plot
- Air Slash
- Heal Bell
- Roost