Introduction:
TL;DR Skip down to the new team.
Well.... The old team. I'll keep this part short for brevity, the Pokémon and their roles;
Scarfed Garchomp, Calm Mind/Baton Pass Espeon, Assault Vest Thundy-T, SD Mega-Lucario, Custap Skarmory, DD Mega-Gyrados
Garchomp was originally to serve as a basic scarfer to outspeed and hit other threats hard. He was usually my starter, used to scout and hit hard, plus no one expects a first turn Outrage which I know sounds stupid, but honestly starting off the game 6-5 first turn is pretty advantageous assuming it got an OHKO, which it did 50% of the time. All of that being said, chomp was basically a fodder/scout without Volt or Turn.
Espeon was there to baton pass Calm Minds, but when I finished the team I realized it would only have one beneficial recipient; Thundy-T. Because of this I changed it from CM/BP + 2 Attacks to CM/BP/Sub/Stored Power. This proved somewhat reliable, but not really.
Thudurus-Therian was on the team because of its speed and massive special attack. I decided to throw on assault vest to compliment CM boosts from Espeon and to provide greater longevity. Obviously this meant I couldn't have any boosting moves which I was fine with, since Thundy-T isn't really bulky enough to set up (un-boosted that is).
Lucario was on the team because it's a hyper offense, and whats more hyper offensive than adaptability Lucario, plus I hadn't used it prior to this team and wanted to try it out.
Skarmory was put on the team to set up hazards and phase.
Gyarados was on the team as a set up sweeper/late game cleaner.
New Team:

Sally (Haxorus) (M) @ Choice Scarf
Ability: Mold Breaker
EVs: 252 Atk / 4 SAtk / 252 Spd
Naive Nature
- Iron Tail
- Outrage
- Earthquake
- Brick Break
Haxorus was used to replace Garchomp, and for a specific reason; Mold Breaker. Rotom-W was terrorizing this team especially with Will-o-Wisp. Haxorus naturally outspeeds all Rotoms, and can spam EQ to his hearts desire, until a flying type or balloon holder comes in. Honestly what I wanted in this set was something that could present and immediate thread as a lead, hit hard with EQ, and hit fairy types hard. Iron Tail is for fairy types, originally for this spot I thought about using Excadrill because it also gets earthquake, outspeeds rotom, and gets Iron Head, but decided to go with Haxorus' power and speed over Excadrill's STAB EQ/Iron Head and accuracy. Brick Break is only here to break screens, since Haxorus also acts as a scout/fodder after it switched out. Outrage for the STAB. EV's to maximize speed and hit hard with base 147 neutral Attack.

Espeon @ Light Clay
Ability: Magic Bounce
EVs: 252 HP / 4 SAtk / 252 Spd
Timid Nature
- Light Screen
- Reflect
- Baton Pass
- Psychic
Ahh the screens. Espeon was switched from a Baton Pass set to this set, which has proven very useful. Usually it gets killed, but the screens are game changing. Baton Pass to keep momentum and psychic to not be left vulnerable if it's the last one alive. Magic Bounce is a huge plus, and allows Espeon to come in and set up easily on slower walls/things that try to set up stuff on my side. EV spread to maximize Bulk and speed to have a better chance of getting up screens.

Lucario @ Focus Sash
Ability: Steadfast
EVs: 4 HP / 252 SAtk / 252 Spd
Modest Nature
- Nasty Plot
- Flash Cannon
- Shadow Ball
- Vacuum Wave
The idea of having mega Luke/2 mega's was scratched and replaced with a NP focus sash set. This set benefits greatly with Defog support. Nasty Plot was chosen over SD for the suprise factor, and to avoid being crippled by WoW. EV's are to maximize Speed and SpAtk. Flash Cannon and Shadow Ball are for coverage and STAB with Flash Cannon, and Vacuum Wave was chosen over Aura Sphere for the priority.

Skarmory @ Custap Berry
Ability: Sturdy
EVs: 252 HP / 232 Def / 24 Spd
Impish Nature
- Stealth Rock
- Defog
- Brave Bird
- Whirlwind
Breaking the Hyper Offensive spirit is Skarmory, whose only move change from the last team was Defog over Spikes, so it can act as my spinner. Custap was chosen to act as a possible lead, and because anything else seemed pointless to me. Rocks are obligatory, Defog to remove hazards, Brave Bird for the STAB and attacking move, and whirlwind to phase out mons trying to set up. I don't remember where I got the EV spread though (I believe it's from the competetive pokedex?).

Charizard @ Charizardite X
Ability: Blaze
EVs: 252 Spd / 252 Atk / 4 HP
Adamant Nature
- Dragon Dance
- Dragon Claw
- Fire Punch
- Earthquake
Mega Charizard-X was chosen because it is in my opinion, one of the best set up sweeper mega evolutions. 130 base attack + tough claws is enough to make anyone quiver, but add DD and this set becomes a monster. I'll be honest, and tell you that I originally thought I was running Jolly, but now it seems silly to not run adamant. Dragon Claw and Fire Punch are for STAB and to both take advantage of Tough Claws, and EQ is for coverage. Mega-Zard's typing makes it a key physical sweeper, because it gets great offensive STAB and is unnaffected by Will-o-Wisp/burn.

Manaphy @ Leftovers
Ability: Hydration
EVs: 252 Spd / 252 SAtk / 4 SDef
Timid Nature
- Tail Glow
- Surf
- Ice Beam
- Shadow Ball
Not really much more to say. Manaphy absolutely destroys teams. This is my main go to once screens are up, since it has base 100 stats across the board, it becomes very bulky and difficult to kill. It gets that great base 100 speed, which I chose to max out since outspeeding can mean a lot on this set. Tail Glow is the reason this set is so deadly, because 2.5x Manaphy behind two screens is nothing to fuck with. Surf/Ice Beam/Shadow Ball for decent coverage ;). Honestly I don't see Manaphy remaining OU for very much longer, even without infinite rain, it still presents a huge threat for OU.
(All of my images come up broken, help please!)