Hey TNT grats on winning team of the week and excellent offense team you have here :D
Ok with Genesect banned your team is without a Steel-type. Although Hippowdon does have great defense without a Steel-type your team is threatenend by powerful Dragon-type attacks like Outrage and Draco Meteor. Latias and Latios stand out as the biggest threats to this team. With Choice Specs Latios can quite easily spam Draco Metoer which threatens your whole team. Calm Mind Latias with Psyshock also looks annoying because it can outspeed and beat Terrakion and can also beat Keldeo with Psyshock, and with no Dragon-type resists if Latias has accumilated some Calm Minds which it can get up against Keldeo and can also get up one against Landorus and Terrakion he can quite easily sweep your team with Dragon Pulse seeing as you have no Dragon-type resists. Their Life Orb sets also look quite menacing for your team with Draco Meteor / Surf / Psychock / Recover Latias or Latios can hit all but Rotom-W on your team super effectively Rotom-W also won't like taking to many Draco Meteors and aside from Thunderwave none of Rotom-Ws moves can do anything to the lati twins.
To help remedy your problem against that Lati twins, provide you with a Steel-type and give you a good sweeper in Genesects place i suggest using Sub+CM Jirachi in the empty slot of your team. With acces to Calm Mind and his Steel-type Jirachi can easily set up on the Lati twins and can also easily switch into their Psyshocks and Draco Meteors. Jirachi can also sponge hits from Tornadus-T, and can also threaten rain teams after he has gotten up a Calm Mind or two which is nice just incase your Rotom-W goes down. With Substitute / Psyshock / Thunderbolt / Calm Mind Jirachi is also a great wall breaker and can break defensive combos like Skarmbliss due to Jirachi having Thunderbolt for Skarmory and 101 Hp Substitutes and Psyshock for Blissey. Jirachis ability to break through defensive cores is great to pave the way for a Landorus or Terrakion sweep. If you feel like you don't need Psyshock you can always use Flash Cannon in that slot, while you won't be able to break through the pink blobs this gives Jirachi the ability to destroy hail teams and helps you against Expert Belt Abomasnow who hits every member of your team super effectivly with Ice Shard / Wood Hammer / Blizzard / Earthqauke. He can also bypass Rock Polish Landorus's speed and ohko him with Ice Shard.
Good luck with the team i hope i helped!