First Competitive semi-rain team. Please critique

[Hindl]

Hey this is my first attempt at team building so any help you can give me would be great.

This is a team that I threw together and really like all of the individual pokemon. However, I think there are some holes, so give a brief overview. This started with me falling in love with Sylveon and wanting to build a team around him. I played around a bit and put together this team.
252 HP / 16 Def / 240 SpD
nature: Relaxed
Defensive Core:

Sylveon @ Leftovers
Ability: Pixilate
EVs: 252 HP / 252 Def / 4 SpA
Nature: Bold
Role: Support/Special Sweep counter
Calm Mind
Hyper Voice
Shadow Ball
Wish

The one that started all of this. I thought Sylveon was incredible when I used one in-game, and wanted to use it in a competitive team. I picked Aggron as the physical tank (below) to support Sylveon, and Sylveon would provide Wish support and be the special tank. However, I kept wanting to use it semi-offensively, and picked goodra as the Special Tank, with Sylveon providing Wish support as well as sweeping abilities. Sylveon exists in a nebulous role on my team, acting as both Offensive and Defensive Support. Wish helps out Aggron and the sweepers, while that monstrous special defense plus CM lets it act as a great Special Sweep Counter, with Shadow ball and HV providing near perfect neutral coverage if any of my sweepers go down.

Mamoswine @ Leftovers
Ability: Thick Fat
EVs: 252 HP / 252 Atk / 4 Def
Nature: Adamant
Role: Physical Tank/Lead
Stealth Rock
Ice Shard
Icicle Crash/Rock Slide
Earthquake

Bulky Stealth Rock lead. Mamoswine's main job is to set up SR then get out until an opportune time arises for it to come out again. Ice Shard gives STAB priority to take out Dragons as well as Gliscor and other threats, while also providing the EQ slot on my team. The last move is Icicle Crash for additional STAB, but Rock Slide could be an alternative to provide better coverage against Talonflame

Goodra @ Damp Rock
Ability: Damp Rock
EVs: 252 HP / 252 Def / 252 SpD
Nature: Bold
Role: Special Tank/Rain/Trapper
Rain Dance
Rest
Infestation
Dragon Pulse / Toxic

The Special Wall of the group, as well as a trapper and Rain Dancer. Rain Dance covers a lot of the weaknesses in my team as well as buffs their strengths. I didn't want to use Politoed, so I threw Goodra in to help taking the special wall burden off of Sylveon. Rain Dance Rest allows for continuous healing. Infestation allows Goodra to trap opponents and kill them. To help this, Dragon Pulse gives Goodra a strong STAB attack, while Toxic helps with trapping. Dragon Pulse is favored since Toxic can't affect the Steel-types roaming the scene.

Offensive:

Scizor @ Scizorite
Ability: Technician
EVs: 252 HP / 252 Atk / 4 SpD
Nature: Impish
Role: Defogger/Volt-Turn/Physical Sweep
U-Turn
Bug Bite / Roost
Defog
Bullet Punch

Part one of the VoltTurn combo. Also, Scizor will be the defogger to take care of any incoming entry hazards. U-Turn is obviously to keep momentum and switch with Rotom-W, and Bullet Punch and Bug Bite provide STABs. Also, Scizor is part of the reason Goodra got introduced, since he functions better under Rain. Bug Bite or Roost is undecided, between wanting a more defensive tank or Offensive Volt-Turn combo. Any advice would be appreciated

Rotom @ ?
Ability: Levitate
EVs: 232 HP / 56 SpA / 220 Spe
Nature: Modest
Role: Volt-Turn/Special Sweep
Volt Switch
Hydro Pump
Discharge / T-Wave
Will-O-Wisp

Second part of Volt-Turn. Volt Switch lets it switch out of threats, while Hydro Pump hits hard and is boosted under Rain. Discharge gives STAB and chance to Paralyze, while T-Wave sacrifices the damage for a more supportive role. Any advice would be great with that. Will-O-Wisp adds status and cripples any physical opponents, which my team could otherwise have trouble with

Volcarona @ Lum Berry
Ability: Flame Body
EVs: 252 SpA / 252 SpD / 4 HP
Nature: Timid
Role: Special Sweeper
Quiver Dance
Bug Buzz
Hurricane
Fiery Dance / Fire Blast

Final member of team. Although not the first pick for a Rain team, he's surprisingly effective. Volcarona sets up under rain with Quiver Dance, and takes advantage of 100% accuracy Hurricanes. This lets me take care of Fighting types who could otherwise rip through my team, as well as any Grass types. Bug Buzz and Fiery Dance provide great Special STAB, with Fiery Dance / Fire Blast reserved for when Rain ends. I'm unsure on the boons of Fiery Dance possibly being redundant with Quiver Dance, but any help would be appreciated.

************************
Alternate for Mamoswine:

Swampert @ Leftovers
Ability: Torrent
EVs: 240 HP / 200 Atk / 68 Def
Nature: Adamant
Role: Offensive Tank
Stealth Rock
EarthQuake
Waterfall
Toxic / Ice Move (Avalanche/Ice Punch)

An alternate for Mamoswine. Swampert is less powerful and has a 4x weakness to grass, but that's its only weakness, and it resists a ton of attacks, as opposed to Mamoswine. Also, it has more balanced defensive stats, allowing it to attack without dying as easily. Stealth Rock sets up, then it has two STABs in Waterfall and EQ to take advantage of that Attack stat. The last move is up for grabs between an ice move to handle dragons as well as grass types if it can't switch out, while Toxic spreads status and can force switches.


Well there's my team. Rate it and let me know what's wrong.
EDIT: Add some more descriptions to make each role more defined

 

[xNaminex]

Pretty Solid team, however, since you really like sylveon, why not play the offensive side to it.
Ive use an AV sylveon on wifi its pretty good.

Sylveon @ Leftovers
Ability: Pixilate
EVs: 252 HP / 252 SpA / 4 SpD
Nature: Modest
Role: Bulky Sweep
Psyshock
Hyper Voice
Shadow Ball
Hidden Power Ground

Psyshock - can take down special walls
Hyper Voice for STAB + Pixilate - for insane damage
Shadow Ball - coverage
HP ground - for the obvious switch to steel/poison type.

 

[Hindl]

Thanks for the reply, I was thinking of something like that, but I decided against it for two reasons.

1. Sylveon acts as a great support with Aggron using Wish, and provides a heal to the entire team. No one on my team has any method of recovery other than Goodra, so Sylveon's Wish passing was essential.

2. I already have two special sweepers on my team and I figured adding another in lieu of support wasn't a great idea. Plus, Rotom-W is a better AV user in my opinion. Sylveon acts as a support/counter sweeper on this team, which is needed. Goodra can take the physical attacks and trap certain sweepers, but doesn't have the same KO potential. Sylveon can come in on special sweepers, tank the hit and possibly force a switch, which would allow CM setup to boost his attack. Plus, Shadow Ball/Psyshock are great, but they need to be boosted to be really effective IMO.

If you have any other tips or advice, or maybe Pokes I should switch out, that'd be great. I really wanna use Sylveon, Scizor and Volcarona, and the others fell into place from those 3.

 

[dinotrek27]

Pretty Solid team you got there even though rain teams are mostly a thing of the past.

First Thoughts... AV rotom? I mean it's pretty solid but you do miss out on will o wisp and thunder wave as support moves as well as pain split and resto chesto for semi -Reliable recovery

Your team overall is pretty solid in terms of synergy. However, I see a pretty big physical weakness. With all the hard hitting earthquakes and Fire moves as well as the team being pretty slow in general. You are quite subseptible to the likes of Garchomp and Excadrill who are able to deal severe damage once your single check Aggron is worn down, fairly easy due to lack of reliable recovery and sylveon can't switch in,as she is a special wall

 

[Asianboy0301]

I agree with dinotrek. Earthquake and fire type moves will wreck your team. I would take out Aggron, put on the Scizorite, and put in an ice-type tank/sweeper/SR setter like Mamoswine. This is mainly because you NEED stealth rock, and having a priority dragon slaying move is nice :).

 

[Hindl]

Hey thanks for the suggestions I think I'll do the Mamoswine switch. I mainly chose Aggron because I saw how great he worked with Sylveon, and I noticed the fire weakness. That's why I decided to try out a semi-rain team despite it being a little lackluster now. I figured rain would be very beneficial to weakening fire moves and strengthening Water/Hurricane/Electric/etc would be great, but the team isn't absolutely dependent on it. I wanted to run Scizorite, but I didn't think he would be bulky enough to take Tank duties. But yeah if I swap out Aggron for Mamoswine that could work great thanks.

I was planning on AV Rotom to add a special sweep, but I actually see now that between Volcarona and Sylveon backing it up, that's not 100% necessary. So you think this Rotom-w would be better if I made him bulkier suppport sweep? Also which item should I use? Pretty heavily taken from the XY preview but slightly modified:

Rotom-W @ ?
Ability: Levitate
EVs: 252 HP / 252 Def / 4 SpA
Nature: Bold
Role: Bulky Volt Switch/Sweep
Volt Switch
Will-O-Wisp
Hydro Pump
T-Wave / Discharge

Also you think Scizor's moveset would be fine and just change his item to Scizorite? Or should I swap out Bug Bite for Roost to increase his durability?

EDIT: Also, Mamoswine is probably best, but what are the thoughts on a defensive tank Swampert w/ SR? Would the weaker Attack and 4x Grass weakness negate it's better all around defenses?