Yea sure why not; let's rate this team.
Conkeldurr @ Assault Vest
Ability: Guts
EVs: 252 Atk / 252 HP / 4 SDef
Nature: Adamant
- Drain Punch
- Mach Punch
- Ice Punch
- Knock Off
Vaporeon @ Leftovesr
Ability: Water Absorb
EVs: 252 HP, 252 Def, 4 Sp. Atk
Nature: Bold
- Wish
- Heal Bell
- Scald
- Protect
Heatran @ Leftovers
Ability: Flash Fire
EVs: 252 HP, 252 Sp. Def, 4 Sp. Atk
Nature: Calm
- Stealth Rock
- Roar
- Lava Plume
- Protect
I've more or less left these three unchanged; Vaporeon's set is standard cleric support so no changes there, and Conkeldurr's set is good to go. I just suggest Ice Punch because otherwise Gliscor will wall you. At least STAB fighting is x1 against Skarmory.
As for Heatran, I've suggested a defensive set because I think you really need it when there's Talonflame around. It's unbelievable how many teams need to carry Heatran just because of that stupid bird. Also Heatran wouldn't be a bad phaser considering all of its immunities and resistances.
Scizor @ Choice Band
Ability: Technician
EVs: 252 HP, 252 Atk, 4 Sp. Def
Nature: Adamant
- Bullet Punch
- U-Turn
- Pursuit/ Defog
- Superpower/ Defog
So I'm suggesting a Band Scizor set instead of Mega-Scizor, and that might not suit your tastes, but just consider it, because I have a Mega-Evo suggestion below. Standard Bullet Punch for Technician, U-Turn to escape from situations like Magnet Pull, and either Superpower or Pursuit for coverage. Defog is the last and final move for clearing hazards, and considering Scizor's coverage, it'll force a lot of Pokemon to switch giving it a free turn to use Defog & switch back out.
If, however, you don't feel that your team needs something with Defog, then of course use both Pursuit & Superpower for coverage.
Mega-Gardevoir @ Gardevoirite
Ability: Trace > Pixelate
EVs: 252 Sp. Atk, 252 Speed, 4 HP
Nature: Timid
- Calm Mind
- Hyper Voice
- Psyshock
- Shadow Ball
Mainly suggesting Gardveoir because of its double fighting resistance, which is what makes it a good partner for Heatran. I've kinda made it a 2 in 1 of Latias and Reuniclus. Bug & Dark are also x1, with its only weaknesses being Ghost, Steel & Poison. I don't really know what answer I have to Ghost types for your team without shifting too many Pokemon around, but considering only Dark and Normal resist/ are immune to Ghost, there actually aren't a lot of options.
Hyper Voice > Moonblast just because it hits through the substitute (and will receive STAB from Pixilate), Psyshock and Shadow Ball for STAB & coverage. You can choose a coverage move over Calm Mind as well, like Thunderbolt, but I would recommend Calm Mind more.
Rotom-Mow @ Choice Scarf
Ability: Levitate
EVs: 252 Sp. Atk, 252 Speed, 4 HP
Nature: Modest
- Volt Switch
- Leaf Storm
- Thunderbolt
- Trick/ Hidden Power Ice
At the moment, you have no answer for ground or electric types, so I'm suggesting Rotom-Mow, which will also fill up the Ground and Water weakness Garvedoir cannot wall for Heatran. At least even with Mold Breaker, Rotom-Mow won't take super effective damage from Excadrill. You can either choose HP Ice to have a quick option to deal with Garchomp, or Trick to free your moves. Finally, Volt Switch for scouting.
I only had time to test it out a few times:
http://replay.pokemonshowdown.com/ou-81927898
http://replay.pokemonshowdown.com/ou-81930309
http://replay.pokemonshowdown.com/ou-81932533
By the way, I had Defog > Pursuit on Scizor and HP Ice > Trick on Rotom-Mow.