Ok If you dont like my answer because its not got many points (because its a good team) or its plain bad then i will happily hide it.
From what i have used with it it has been rather good and there are not many notable changes i can see.
Im going to use the importable copy that i used after i tested the origional team.
Ninetales (F) @ Leftovers
Trait: Drought
EVs: 132 HP / 252 SAtk / 124 Spd
Modest Nature (+SAtk, -Atk)
- Fire Blast
- Hidden Power [Ground]
- Will-O-Wisp
- SolarBeam
Venusaur (M) @ Life Orb
Trait: Chlorophyll
EVs: 40 HP / 252 Atk / 216 Spd
Adamant Nature (+Atk, -SAtk)
- Power Whip
- Growth
- Earthquake
- Return
Heatran (M) @ Air Balloon
Trait: Flash Fire
EVs: 252 HP / 252 SAtk
Modest Nature (+SAtk, -Atk)
- Lava Plume
- Hidden Power [Ice]
- Earth Power
- Stealth Rock
Espeon (M) @ Leftovers
Trait: Magic Bounce
EVs: 252 HP / 4 SAtk / 252 Spd
Timid Nature (+Spd, -Atk)
- Psyshock
- Morning Sun
- Calm Mind
- Hidden Power [Fire]
Dragonite (M) @ Leftovers
Trait: Multiscale
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Dragon Dance
- Dragon Claw
- ExtremeSpeed
- Fire Punch
Mamoswine (M) @ Choice Scarf
Trait: Snow Cloak
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Earthquake
- Superpower
- Stone Edge
- Icicle Spear
Ninetails
Ok so i see why you used energy ball and its ok to keep it but 286 spatk is not anything special, so i tried solarbeam and i found it much more effective, after all its not like your going to stay in for tyranitar and politoad, as it will be a 2hit ko, probably 3 for tyranitar and 3 for a defsive politoad that is with energy ball, by then your dead.
But everything is fine here.
Venasaur
Ok once again i went for power over accuracy, as seed bomb even with +2 atk was only doing around 70% on a neutral hit with good def.
I also used life orb as black sludge wasnt working to well as life orb has giving it 375 atk without any boosts which meens you can do good damage without wasting a turn.
Hidden power fire is also an option as it gets sun boost and after growth it gets 424 spatk.
But that is optional.
Heatran
The moveset was fine here though it was not tanking like a tank, its was lacking offence and calm nature wasnt doing much as almost all super effective hits came from fighting and earth moves which as you know are almost all pysichal.
I found modest much more effective.
Espeon
Once again set was fine, worked well nothing major worth changing.
Dragonite
I personally prefer life orb on dragonite to do that extra damage, you should try it as once a dragon dance is up it wrecks whole teams.
But leftovers are fine i made a 6 pokemon sweep with this set, considering i added fire punch.
Fire punch covers allot and kills ferrothorn planning to wall you.
If you prefer earthquake i didnt actually find extreme speed very usefull not many priority moves appart from ice shard hit dragonite hard.
Mamoswine
I didnt like his role on the team much its ability was almost useless as hail is rarely seen but mainly because its so frail, so i tried thick fat as that helped allot but it really limited its movepool.
Also icicle spear wasnt reliable so i suggest a replacement ill give 3.
But Mamoswines set is good if you dont want it.
Gliscor
It walls most of your major weaknesses appart from ice, which is easyly dealed with.
It looses its water weakness and can run a swords dance poison heal set.
Scizor
Covers some major weakness plus adds more priority to your team which will take care of shell smash cloyster which will sweep your team.
Choice band and swords dance sets are good, i personally prefer swords dance.
Hippowdon
I actually havent tested this one yet but it is a good counter for a sand team.
It has access to sand force which will troll tyranitar, not many sand teams can counter a hippowdon.
Out of the two i tested scizor proved rather effective and a good politoad counter, but i suggest trying hippowdon.