I'm thinking because of this lack of switches, we probably need at least one whirlwind pokemon and one pokemon with moves such as clear smog or haze to deal with stat boosting threats. However, the only pokemon that we have that can use clear smog is castform, and seeing as castform is rather suboptimal, fairy pokemon that can set up such as Azumarill and Clefable will be threatening to us this time around. Also, we only have access to haze on Dodrio and Xatu, so once again, whirlwind and roar will be very optimal.
Threats to look out for! (Mega's in Bold)
Azumarill(Easy set up with belly drum, priority, type advantages), Clefable(Magic Guard, Setup in special attk and def. as well as def., type advantage, Unaware), Mega Gardevoir(Sound Stab Move, high stats in special attk and def, access to calm mind and W-o-W), Greninja(Need I even explain?), Gyarados/Mega Gyarados(Intimidate/Moxie/Mold Breaker, good movepool, sky high offensive stats, Dragon Dance set ups, type advantage), Keldeo(Set up Calm Mind, type advantage), Mandibuzz(Bulk and type advantage), Mega Mawile(Sky High Attack, sucker punch, swords dance set up, type advantage), Quagsire(Unaware makes it utterly immune to stat boosts, defensive threat), Sylveon(Pixilate Hyper Voice, type advantage), Togekiss(Paraflinch4dayz, type advantage), Crawdaunt(Adaptability, knock off, dragon dance set up), Klefki(Prankster, screens, twave, swagplay{notsureifallowedornot}), Manaphy(Tail Glow).
Threats for our team! (Mega's in Bold)
Breloom(Spore, Poison Heal, Technician, Type Advantage), Blissey/Chansey(Bulk and status), Conkeldurr(Sky High Attack, great abilities, type advantage), Mega Gardevoir(Sound Stab Move, high stats in special attk and def, access to calm mind and W-o-W), Keldeo(Set up Calm Mind, type advantage), Mega Medicham(Pure Power, access to priority and fake out, type advantage, team mascot), Smeargle(ANYWAY YOU WANT HIM THAT'S THE WAY YOU NEED HIM), Hawlucha(Type Advantage, unburden, hone claws set up, highly offensive move pool), **STILL A WORK IN PROGRESS**