I don't care if there are two answers already, when a team has problems, those problems need fixed.
You have multiple major weaknesses. Two of them are to types in general and the other is to Speed.
Your first weakness is to Water types. Now this is obviously a huge problem. This is UU after all, home to the bulky water. We've got Milotic, Swampert, Suicune, and Blastoise here. Your second weakness is one to Fighting type Pokemon. Thanks to the recent UU additions, this is also a huge problem. This is a tier that allows Machamp, Hitmontop, Heracross and now Scrafty and Mienshao. Scrafty and Mienshao in particular are looking to be major parts of the UU metagame. We've also got some Fighting types from RU coming in, like Hitmonlee. The final weakness is to fast Pokemon. Your fastest Pokemon is Mienshao at 309 Speed.
Now, to deal with bulky Waters, I can think of no better Pokemon than Zapdos. Zapdos is able to launch powerful Thunderbolts at the foe, Sub up against Toxic, Roost of any weak attacks, and hit Swampert for x4 damage with HP Grass. Zapdos is also able to retaliate against Pressure stalling Suicune with a Pressure of its own. So it will make for an excellent addition to your team. I think the best Pokemon to replace is Honchkrow, so that you don't increase your Stealth Rock weakness.
FOr dealing with Fighting types, I find nothing works better than a Cofagrigus. That Mummy is what makes it so great, allowing it to launch Will-o-wisps against Guts and Shed Skin. We'll replace the Azelf I saw you had on your team for it.
I saw you had a Nidoking on your team. TO deal with faster Pokemon, I think that will be all that is needed. We can make it a Scarfer and that should help you out a lot.
Now for some changes here and there. Spoink covered a lot of them, so this will be mainly be reitterating what he said.
On Mienshao replace Acrobatics for Fake Out. This works out great with Mienshao's focus on switching in and out a lot. I agree with Spoink's suggestions on Blastoise, adding in Rapid Spin, Scald, and Roar. And also Close Combat on Arcanine. I would definately suggest a Jolly Nature for Mienshao though. This allows it to make use of the base 105 Speed stat it has and outspeed foes who go Jolly, allowing it to Fake Out and then U-Turn to a new guy who can take hits. The damage this causes also helps.
Mienshao (F) @ Life Orb
Trait: Regenerator
EVs: 252 Atk / 4 Def / 252 Spd
Jolly Nature (+Spd, -SAtk)
- U-turn
- Hi Jump Kick
- Fake Out
- Stone Edge
Blastoise (M) @ Leftovers
Trait: Torrent
EVs: 252 HP / 252 SDef / 4 Spd
Calm Nature (+SDef, -Atk)
- Rapid Spin
- Roar
- Toxic
- Scald
Arcanine (M) @ Life Orb
Trait: Intimidate
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- ExtremeSpeed
- Flare Blitz
- Close Combat
- Wild Charge
Nidoking (M) @ Choice Scarf
Trait: Sheer Force
EVs: 4 Def / 252 SAtk / 252 Spd
Timid Nature (+Spd, -Atk)
- Fire Blast
- Sludge Wave
- Shadow Ball
- Earth Power
Cofagrigus (M) @ Leftovers
Trait: Mummy
EVs: 248 HP / 252 Def / 8 SDef
Bold Nature (+Def, -Atk)
- Will-O-Wisp
- Pain Split
- Shadow Ball
- Hidden Power [Fighting]
Zapdos @ Leftovers
Trait: Pressure
EVs: 4 HP / 252 SAtk / 252 Spd
Timid Nature (+Spd, -Atk)
- Thunderbolt
- Roost
- Hidden Power [Grass]
- Substitute
