Ok, so, now for a little introduction about how I made this team. I'd been using a sand team for most of 5th gen, but wanted to move on. I originally tried using rain, but it didn't really work for me, maybe it's not my style. So, I decide to try hazards, so I made this team!
(Changes in bold)
It wouldn't be a hazards team without Skarmory!
Next I added ferrothorn, because it's awesome and I love it.
Then, as my team was weak to fire, and was in need of a SR layer, I added heatran.
I needed a spin blocker, and I jumped at the chance to use SubDisable Gengar, it's awesome!
Then I added dragonite, as he can phaze and sweep.
Finally I added Tentacruel as he too can lay down hazards, and spin as well.
I replaced Ferrothorn with Latias. Ferrothorn wasn't performing well, and latias's wish passing and phazing abilites are a great addition to the team
Skarmory @ Leftovers
Sturdy
Impish
EVs: 252 HP, 252 Def, 4 Sp.Def
Moves:
--Spikes
--Whilwind
--Roost
--Brave Bird
Latias @ Leftovers
Levitate
Bold
EVs: 252 HP, 252 Def, 4 Speed
Moves:
--Calm Mind
--Roar
--Wish
--Dragon Pulse
Heatran @ Leftovers
Flash Fire
Calm
EVs: 252 HP, 252 Sp.Def, 4 Def
Moves:
--Substitute
--Roar
--Steath Rock
--Lava Plume
Gengar @ Black Sludge
Levitate
Timid
EVs: 252 Sp.Atk, 252 Speed, 4 HP
Moves:
--Substitute
--Disable
--Shadow Ball
--Focus Blast
Dragonite @ Lum Berry
Multiscale
Jolly
EVs: 4 HP / 252 Att / 252 Speed
Moves:
--Dragon Dance
--Earthquake
--Fire Punch
--Dragon Claw
Tentacruel @ Black Sludge
Rain Dish
Bold
EVs: 252 HP, 212 Def, 44 Speed
Moves:
--Toxic Spikes
--Rapid Spin
--Scald
--Protect
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Well, that's it! Thanks for reading, all comments and critism are appreciated!
(Changes in bold)
Teambuilding Process

It wouldn't be a hazards team without Skarmory!


Next I added ferrothorn, because it's awesome and I love it.



Then, as my team was weak to fire, and was in need of a SR layer, I added heatran.




I needed a spin blocker, and I jumped at the chance to use SubDisable Gengar, it's awesome!





Then I added dragonite, as he can phaze and sweep.






Finally I added Tentacruel as he too can lay down hazards, and spin as well.






I replaced Ferrothorn with Latias. Ferrothorn wasn't performing well, and latias's wish passing and phazing abilites are a great addition to the team
The Team in Detail

Skarmory @ Leftovers
Sturdy
Impish
EVs: 252 HP, 252 Def, 4 Sp.Def
Moves:
--Spikes
--Whilwind
--Roost
--Brave Bird
Nothing much to say here, you all know the set. Hazards, phazing, recovery. I've gone with max defence, so I can wall the hell out of most phsyical attackers and set up hazards. Special Attacks are absorbed by heatran, who is specially defensive

Latias @ Leftovers
Levitate
Bold
EVs: 252 HP, 252 Def, 4 Speed
Moves:
--Calm Mind
--Roar
--Wish
--Dragon Pulse
Latias is on the team, mainly, to provide wish pass support, which is especially useful with Dnite. It's the normal set (but with recover replaced with wish) so that it can set up with calm mind, sweep and phaze too.

Heatran @ Leftovers
Flash Fire
Calm
EVs: 252 HP, 252 Sp.Def, 4 Def
Moves:
--Substitute
--Roar
--Steath Rock
--Lava Plume
SubRoar heatran has proved very useful for me on this team. He absorbs a lot of special attacks, has some good resistances, subs on the switch, lays down SR and phazes. Lava plume is there to make use of flash fire and prevent from being taunt bait, the high burn chance is nice too.

Gengar @ Black Sludge
Levitate
Timid
EVs: 252 Sp.Atk, 252 Speed, 4 HP
Moves:
--Substitute
--Disable
--Shadow Ball
--Focus Blast
SubDisable Gengar is one of my favourite pokemon for competitive usage. Thanks to disable, it can counter a lot more things than it could without it. He also acts as the spin-blocker for my team. The set is standard, so there's little to explain here.

Dragonite @ Lum Berry
Multiscale
Jolly
EVs: 4 HP / 252 Att / 252 Speed
Moves:
--Dragon Dance
--Earthquake
--Fire Punch
--Dragon Claw
I opted, thanks to AntiMetagame's suggestion, to switch to an offensive Dragonite set. The Phazer/Sweeper Hybrid is probably not as effective as a dedicated set. DD + Dragon Claw are the main sweeper's tools here, I've gone with Dragon Claw over Outrage as I hope all the hazards will make up for the drop in power. Earthquake and Fire Punch are coverage. I'm thinking of putting extremespeed in there though....

Tentacruel @ Black Sludge
Rain Dish
Bold
EVs: 252 HP, 212 Def, 44 Speed
Moves:
--Toxic Spikes
--Rapid Spin
--Scald
--Protect
Last but not least, is tentacruel. It T-spikes, removes hazards (including those nasty rocks that hurt poor Dragonite) and can wall quite effectively too. Scald is for the odd burn/not being taunt bait. The 44 speed EVs are to outspeed common threats, and often allow it to get another layer of T-spikes down before being taunted, that kind of thing.
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Well, that's it! Thanks for reading, all comments and critism are appreciated!