Mono-Electric is one of the weaker monotype team to build around and one of the most difficult to use. This is down to three flaws:
- No access to hazards outside the frail, situational Galvantula or the weak Stunfisk
- Little to nothing against popular threats such as Mega-Venusaur or Hippowdon
- Lack of dedicated Physical attacker which means you'll struggle against Chansey
Rotom-Heat serves little purpose in this team to be honest. Rotom-Wash could on the other hand allow you to threaten Mono-Ground teams. I recommend you to make the change:
Rotom-Wash @ Leftovers
Trait: Levitate
EVs: 248 HP / 252 SpD / 8 Spe
Calm Nature
- Will-O-Wisp / Toxic
- Hydro Pump
- Volt Switch
- Pain Split
Also another thing. While I generally do not advocate the use of two Pokémon who share the exact same typing, Thundurus is an extremely powerful Pokémon in a Mono-Electric team, he's like a blessing you're missing out right now. The Wallbreaker set could allow you to reliably check Porygon2, Chansey and many more defensive Pokémon:
Thundurus @ Leftovers / Life Orb
Ability: Prankster
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
- Nasty Plot
- Thunderbolt
- Hidden Power Flying / Knock Off
- Focus Blast / Grass Knot
I prefer Leftovers, Knock off and Focus Blast but playtesting really will determine what you should use. Thundurus should be your go-to against Stall teams and your ultimate wallbreaker.
Conversely, Thundurus-T could be an interesting alternative albeit slightly underperforming:
Thundurus-T @ Leftovers
Ability: Defiant
EVs: 4 SpD / 252 SpA / 252 Spe
Modest Nature
- Nasty Plot
- Agility
- Thunderbolt
- Hidden Power Flying
He kills Mega-Venusaur and all defensive Pokémon like no other Pokémon, but does this justify to tribute his cousin's superior speed tier and better ability? The decision is up to you.
For Manectric, I'll recommend Overheat instead of Flamethrower because Manectric is a fast pivotal Pokémon that sets the mood for your sweepers; he can afford the extra power since you'll be switching a lot.
Electivire needs an item. Choice Band, Expert Belt, Life Orb... you cannot leave it itemless.
I am not a fan of AV Raikou but since Mono-Electric plays so aggressively, it's only fair to have a reliable specially bulky Pokémon.
That's all I have to say. Good luck in running an underrated but off-the-conventions, functional team such as a Mono-Electric, and mainly, have fun.