ORAS OU First RMT thread of mine, I think its pretty tough.

[Deathspa202]

Sylveon @ Leftovers
Ability: Pixilate
EVs: 252 HP / 220 Def / 36 SpD
Bold Nature
- Wish
- Heal Bell
- Protect
- Hyper Voice

I have Sylveon on my team for three big reasons. Number one, s/he can switch in to dragon type moves by Lati@s that attempt to take out my Garchomp. Number two, my team desperately needed some SpD bulk. Finally s/he provides my team with much needed wish support. I would almost prefer Clefable on my team but I love having Sylveon's Special bulk.

Heracross @ Heracronite
Ability: Guts
EVs: 252 Atk / 4 Def / 252 Spe
Adamant Nature
- Close Combat
- Pin Missile
- Rock Blast
- Swords Dance

I have Heracross on my team because its in my top ten favorite Pokemon, lame reason I know but s/he fits really well in this physical sweeper position. It's synergy with Thundurus is pretty fantastic, I'll explain later. If I can predict switch ins however rock blast can take out Talonflame. Pin Missile 2HKOs Ferrothorn without an SD boost and OHKOs Greninja and Slowbro (idk if it OHKOs mega Slowbro.) Rock Blast also covers Gliscor and Gyrados.

Rotom-Wash @ Chesto Berry
Ability: Levitate
EVs: 248 HP / 216 Def / 44 Spe
Bold Nature
- Volt Switch
- Hydro Pump
- Will-O-Wisp
- Rest

Rotom-W is nice to have on the team mainly to cripple Physical Sweepers. Will-O-Wisp is endlessly useful. Hydro Pump is a powerful STAB move to hit Gliscor and Landorus. Volt Switch makes it a great pivot, especially against flying types that threaten Heracross. I put Rest on it because I like to have some recovery on every poke I can.

Garchomp @ Lum Berry
Ability: Rough Skin
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Swords Dance
- Earthquake
- Dragon Claw
- Rock Slide

Garchomp is just such a fantastic physical sweeper, throw a SD on top of that and I becomes nearly unstoppable. I chose Earthquake and Dragon Claw as the go to STAB moves. I know a lot of people prefer Outrage, but being locked into it allows for some annoying switch ins. Because I don't have Outrage it seems weird to have a Lum Berry on it w/o Outrage, but getting burned makes me so frustrated. Rock Slide gives some much needed coverage against Ice and Flying types.

Heatran @ Choice Scarf
Ability: Flash Fire
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Overheat
- Flamethrower
- Flash Cannon
- Earth Power

Heatran with Choice Scarf I so freaking speedy, I love it. It also provides some much needed SpA potential to the team. Flash Cannon provides much needed coverage against Fairies. Overheat is a fantastically powerful STAB move but because of its SpA drops Flamethrower provides a little more stable sweep. Earth Power takes out other Heatran w/o Air Balloon and Rock types.

Thundurus (M) @ Life Orb
Ability: Prankster
EVs: 76 Atk / 180 SpA / 252 Spe
Naive Nature
- Thunderbolt
- Knock Off
- Thunder Wave
- Hidden Power [Ice]

Thundurus checks Talonflame and other Flying threats to Heracross with Thundebolt, hits Lati@s, Ghost and other Psychic types hard with Knock off. Hidden Power Ice annihilates Landorus. Thunder Wave is crippling when facing Garchomp and Heracross as well.

 

[davidTheMaster]

Hey dude to help you I suggest you this

For

run Leftovers over Chesto Berry and Pain Split over Rest For to do of damages on the pokemon opposing and recover some of damages

For

run Hidden Power Ice over Overheat for everything that is Dragon/Flying/Grass/Ground type

 

[Deathspa202]

Thank you. Other than that are my EV spreads and type cores alright?

 

[davidTheMaster]

Yes your other spread is good, just if you want on Garchomp and Heatran you've put "Dragonclaw" and "Flamethrower" in my opinion, playing of moves with more power such as Outrage and Fire Blast for don't fall on of rolls

 

[tko]

Hey Deathspa202! Your team is looking very solid to me! One thing I would like to point out is yout team is lacking a good lead and hazards. This can be changed by using Offensive LeadChomp.
Set

Hide

Garchomp @ Focus Sash
Ability: Rough Skin
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Stealth Rock
- Swords Dance
- Outrage
- Earthquake

With this set, Garchomp now becomes a great lead (if the opponent has something like Mamoswine, you are probably not going to want to lead with chomp)
as well as still hitting as hard with Swords Dance. You are missing out on Rock Slide, but that doesn't hit anything significant except for Togekiss, but you have Rotom, Thundurus, and Heatran for Togekiss anyway. With this, you get Stealth Rocks, which allow your mons to get the opponent mons worn down easier. This compliments Mega Heracross greatly, as with its huge attack stat and Stealth Rocks, not much is going to appreciate any hits. After all, Mega Heracross has limited checks.

Hope this helps!