Ok, well this team looks awesome, and it's been a while I didn't answer any RMTs so I'm kind of rusty, but hey, I'll give it a shot.
Rotom-S. Nice, very nice. Timid over Modest to outspeed +2 Gorebyss and Scarfed Sawk. Also, you could try HP Grass > Thunderbolt as I've been testing it since some time and it works fine. It's coverage against those nasty Rock types.
No HP Rock on Amoonguss. You have no SAtk EVs on him so it won't be doing too much damage. I suggest converting him into a Special Wall, as you already have one of the best Physical Walls in the tier, Alomomola.
Amoonguss (F) @ Leftovers
Trait: Regenerator
EVs: 252 HP / 244 SDef / 12 Spd
Calm Nature (+SDef, -Atk)
- Spore
- Giga Drain
- Sludge Bomb
- Stun Spore
Double Status + Special Wall makes him a great Pokémon, and he causes a lot of switches. This set doesn't require any explanations.
Of course, to your demand, I have to replace Amoonguss (Dimwit xD). Anyways, you wanted to try Porygon, well here he is. Just in case you don't like him, I'll give you another choice.
Porygon @ Eviolite
Trait: Trace
EVs: 252 HP / 252 SDef / 4 SAtk
Calm Nature (+SDef, -Atk)
- Ice Beam
- Discharge
- Toxic
- Recover
I'm going to post Smogon's description:
With a combination of awesome bulk brought on by Eviolite, useful support options, and Recover, Porygon can act as a stoic status platform and defensive pivot. In fact, it is impossible for any singular unboosted special attack to OHKO Porygon. Even the mighty Choice Specs Exeggutor can only manage to deal about 75% at most to it with its Leaf Storm. Ice Beam and Discharge together hit everything neutrally bar the likes of Rotom-F and Shedinja, the latter also having a 30% chance of paralyzing its target. Toxic allows Porygon to stall out bulkier Pokemon, often allowing it to beat Pokemon such as Lickilicky, who can otherwise brush off any and all of Porygon's attacks. Have fun with him!
OR...
Kecleon @ Leftovers
Trait: Color Change
EVs: 252 SDef / 252 HP / 4 Atk
Careful Nature (+SDef, -SAtk)
- Knock Off / Aqua Tail
- Return
- Thunder Wave
- Recover
Knock Off if you don't have it on Alomomola. If you do have it, go for Aqua Tail. Return is nice STAB. Thunder Wave is great team support while Recover is very reliable recovery.
OR....
Just in case you don't like the two previous ones mentioned... Specially Defensive Gardevoir!
Gardevoir @ Leftovers
Trait: Trace
EVs: 252 SDef / 252 HP / 4 SAtk
Calm Nature (+SDef, -Atk)
- Wish
- Heal Bell
- Psychic
- Protect
Not much to say.
Alomomola as a Special Wall? No way.... He works way better as a Physical Wall.
Alomomola @ Leftovers
Trait: Regenerator
EVs: 252 HP / 252 Def / 4 Atk
Impish Nature (+Def, -SAtk)
- Knock Off / Waterfall
- Wish
- Protect
- Toxic
Why do you have Healer on him? Now, you have the traditional Alomoonguss Defensive core, the best Defensive core in the tier. Anyways, this is set Mike's Knock Off set, but some people prefer Waterfall over Knock Off as Skuntank walls the set otherwise. The rest doesn't need any explanations.
Why do you have a Misdreavus? Your team is way to Defensively inclined, we'll be replacing him for Ludicolo, THE premier Special Attacker in the tier now.
Ludicolo (M) @ Life Orb
Trait: Swift Swim
EVs: 4 HP / 252 SAtk / 252 Spd
Modest Nature (+SAtk, -Atk)
- Rain Dance
- Hydro Pump
- Giga Drain
- Ice Beam
I already made a description for this guy, so, here it is.
Offensive Rain Dance Ludicolo is as good in Defense as in Offense, with a great typing giving him a quad resistance to Water-types. Once this guy sets up Rain Dance, the only thing that can stop him is Rain Dish Ludicolo, who is getting popular for being able to counter Offensive Rain Dance Ludicolo. The moves are pretty self-explanatory. Rain Dance starts rain while Hydro Pump is Rain-boosted STAB. Giga Drain is STAB and reliable recovery while Ice Beam is additional coverage and hits Grass-types for super-effective damage.
Well, since I used Ditto against Riles, I feel bad :P. This thing is cheap as hell, and plus, like Trachy said, most people are prepared against it. Since you don't have a Hazards setter, I suggest Golurk.
Golurk @ Expert Belt
Trait: No Guard
EVs: 92 HP / 252 Atk / 164 Spd
Adamant Nature (+Atk, -SAtk)
- Earthquake
- Shadow Punch
- DynamicPunch
- Stealth Rock
Well, here's something exceptional. After S-Rock damage, Shadow Punch, which is STAB, 2HKO'es max Defense Musharna. Adamant Nature allows him to get as much power as possible, while 164 Spd allows him to outspeed Garbodor and OHKO with Earthquake before he lays his filthy Toxic Spikes. Other than that, DynamicPunch's confusion effect is EXTREMELY helpful, and it nails a lot of KOs. Stealth Rock is there for an obvious reason.
Well, since Absol is staying in NU, he's a better trapper than Skuntank. Here's a good Trapping set:
Absol (M) @ Life Orb
Trait: Super Luck
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Sucker Punch
- Superpower
- Night Slash
- Pursuit
No explanations required.
Well, I hope I helped your team a bit, even though my suggestions are kind of minor.
