Then I may as well post mine. Although this will always be subjective, I feel like this is as close to a 'perfect' BP team you can get. I have made many adjustments and have ended up with this team. It still has its counters as does any team.
Ninjask @ Mental Herb
Trait: Speed Boost
EVs: 4 HP / 252 Atk / 252 Spd
Jolly Nature
- Baton Pass
- Substitute
- Aerial Ace
- Protect
This is what I generally use for leading. 252 speed and jolly ensures that I can sub against most of the metagame. If a choice scarf is predicted (i.e. Latios or even Jirachi) I can protect and be 100% faster the next turn. With this set I am also always faster than Rotom-W with choice scarf, allowing me to sub first turn. Aerial Ace is pretty much only for Breloom (or the odd Heracross). White Herb is excellent for taunt or encore leads such as Sableye and Politoed: you can protect the first turn and then use substitute, Mental Herb will cure the encore or taunt and allows you to baton pass +2 speed to Espeon who is immune to most non-attacking moves.
Umbreon @ Leftovers
Trait: Synchronize
Shiny: Yes
EVs: 252 HP / 252 Def / 4 SDef
Bold Nature
IVs: 0 Atk
- Baton Pass
- Heal Bell
- Yawn
- Substitute
Umbreon is an important pivot. Mr. Mime, Espeon and Mew really don't like STAB crunches and physically defensive Umbreon boasts an impressive resilience. It can yawn the opposing pokemon and then baton pass to switch in to the appropriate counter: switching has priority over baton pass, so the opponent will switch before you have to make your switch, allowing you to baton pass to the appropriate counter. If the opponent doesn't switch you get a free turn, as he will fall asleep the next turn. Heal bell cures status, I have found this to be the superior option (the only other one is pretty much taunt).
Vaporeon @ Leftovers
Trait: Hydration
Shiny: Yes
EVs: 252 HP / 252 Def / 4 Spd
Bold Nature
IVs: 0 Atk
- Baton Pass
- Acid Armor
- Roar
- Substitute
This is what we lead with when the enemy has Cloyster. Acid armor the first turn, roar the second. Keep in mind that crits (or flinches with King's Rock) are pretty likely on skill linked rock blast, so try to get rid of Cloyster as soon as possible. Roar on the first turn is a possibility as well, but nearly every Cloyster lead I have encountered Shell Smashes first. Hydration is preference, can also be water absorb.
Mew @ Leftovers
Trait: Synchronize
Shiny: Yes
EVs: 144 HP / 252 SDef / 114 Spd
Calm Nature
IVs: 0 Atk
- Baton Pass
- Barrier
- Thunderbolt
- Amnesia
264 speed allows us to always outspeed Breloom and non-scarf Cloyster and additionally grants us 398 speed with +2. Thunderbolt to hit dark pokemon and Cloyster. Specially defensive so I can swap it in against weather abusing pokemon and Amnesia myself up.
Espeon @ Leftovers
Trait: Magic Bounce
EVs: 252 HP / 4 Def / 252 SDef
Serious Nature
IVs: 0 Atk
- Baton Pass
- Calm Mind
- Stored Power
- Substitute
Clean-up. To give you an idea of the power: I OHKO'd a Jirachi (x4 psychic resist) from full health to zero.
Mr. Mime @ Leftovers
Trait: Soundproof
EVs: 252 HP / 4 Def / 252 SDef
Calm Nature
IVs: 0 Atk
- Baton Pass
- Calm Mind
- Barrier
- Encore
Soundproof. Blocks roar and perish song and can encore pokemon who are trying to set-up, allowing you to roar them out with Vaporeon. Specially defensive because it's a Volcarona switch-in, Mr. Mime is immune to Bug Buzz.
Q: Why no Scizor?
A: I'm not afraid of Cloyster and don't need Swords Dance. There isn't really anything I need Scizor for aside from perhaps resistances, but I haven't had any problems with bug attacks.
Q: Why no Smeargle? How do you deal with whirlwind/roar? Don't you need ingrain/spore?
A: Not really, I have Magic Bounce, Mr. Mime and Roar on Vaporeon to deal with phazing. I have tested both Aqua Ring and Ingrain on Smeargle and the extra regen doesn't do as much as you'd think it'd do.
Q: How do you deal with Haze?
A: You don't, but I have not seen Haze in over 300 games. Theoretically you could stall out the opponent, but then prepare for a 300+ turn game which you may still lose because you have no entry hazards and limited offensive moves (calm mind's PP on Mr. Mime and Espeon vs. Haze, Stored Power + Thunderbolt PP vs. whatever the opponent has). If the opponent has entry hazards, status, knock off or basically anything in combination with Haze you are probably flat-out going to lose.
Q: Dragon tail and Circle throw? Clear smog?
A: Substitute
IMPORT
Umbreon @ Leftovers
Trait: Synchronize
Shiny: Yes
EVs: 252 HP / 252 Def / 4 SDef
Bold Nature
IVs: 0 Atk
- Baton Pass
- Heal Bell
- Yawn
- Substitute
Vaporeon @ Leftovers
Trait: Hydration
Shiny: Yes
EVs: 252 HP / 252 Def / 4 Spd
Bold Nature
IVs: 0 Atk
- Baton Pass
- Acid Armor
- Roar
- Substitute
Ninjask @ Mental Herb
Trait: Speed Boost
EVs: 4 HP / 252 Atk / 252 Spd
Jolly Nature
- Baton Pass
- Substitute
- Aerial Ace
- Protect
Mew @ Leftovers
Trait: Synchronize
Shiny: Yes
EVs: 144 HP / 252 SDef / 114 Spd
Calm Nature
IVs: 0 Atk
- Baton Pass
- Barrier
- Thunderbolt
- Amnesia
Espeon @ Leftovers
Trait: Magic Bounce
EVs: 252 HP / 4 Def / 252 SDef
Calm Nature
IVs: 0 Atk
- Baton Pass
- Calm Mind
- Stored Power
- Substitute
Mr. Mime @ Leftovers
Trait: Soundproof
EVs: 252 HP / 4 Def / 252 SDef
Calm Nature
IVs: 0 Atk
- Baton Pass
- Calm Mind
- Barrier
- Encore
Trait: Synchronize
Shiny: Yes
EVs: 252 HP / 252 Def / 4 SDef
Bold Nature
IVs: 0 Atk
- Baton Pass
- Heal Bell
- Yawn
- Substitute
Vaporeon @ Leftovers
Trait: Hydration
Shiny: Yes
EVs: 252 HP / 252 Def / 4 Spd
Bold Nature
IVs: 0 Atk
- Baton Pass
- Acid Armor
- Roar
- Substitute
Ninjask @ Mental Herb
Trait: Speed Boost
EVs: 4 HP / 252 Atk / 252 Spd
Jolly Nature
- Baton Pass
- Substitute
- Aerial Ace
- Protect
Mew @ Leftovers
Trait: Synchronize
Shiny: Yes
EVs: 144 HP / 252 SDef / 114 Spd
Calm Nature
IVs: 0 Atk
- Baton Pass
- Barrier
- Thunderbolt
- Amnesia
Espeon @ Leftovers
Trait: Magic Bounce
EVs: 252 HP / 4 Def / 252 SDef
Calm Nature
IVs: 0 Atk
- Baton Pass
- Calm Mind
- Stored Power
- Substitute
Mr. Mime @ Leftovers
Trait: Soundproof
EVs: 252 HP / 4 Def / 252 SDef
Calm Nature
IVs: 0 Atk
- Baton Pass
- Calm Mind
- Barrier
- Encore