Dont have a lot to say but you say Ferrothorn is a big annoyance and I agree. So I would recommend Dual Dance Landorus-T > Garchomp. The item is up to you, if you want to damage ferro more go with Earth Plate but if you find yourself weak to Ice types and such, use Yache Berry. I just think it's better because it's more useful defensively while also having a higher attack stat to pressure all sorts of teams with that great edgequake coverage.
Gyarados-Mega @ Gyaradosite
Ability: Intimidate
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Dragon Dance
- Waterfall
- Crunch
- Bounce
Garchomp @ Salac Berry
Ability: Rough Skin
EVs: 12 HP / 244 Atk / 252 Spe
Jolly Nature
- Substitute
- Swords Dance
- Outrage
- Earthquake
Metagross @ Shuca Berry
Ability: Clear Body
EVs: 248 HP / 252 Atk / 8 SpD
Adamant Nature
- Stealth Rock
- Meteor Mash
- Ice Punch
- Hammer Arm
Latias @ Life Orb
Ability: Levitate
EVs: 72 HP / 184 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Draco Meteor
- Psyshock
- Defog
- Healing Wish
Weavile @ Choice Band
Ability: Pressure
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Knock Off
- Ice Shard
- Icicle Crash
- Pursuit
Raikou @ Leftovers
Ability: Pressure
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk / 30 Def
- Calm Mind
- Thunderbolt
- Hidden Power [Ice]
- Toxic
I've spent a lot of time learning about the basics of team building and hoping for feedback on one of my favorite teams. I wanted to build around 3 Attacks Mega Gyarados, who is definitely an uncommon threat that most teams aren't prepared for. I liked that he was just as useful non-mega as he was a mega, so I wanted to build a team that takes advantage of his two faces. Weavile is my wallbreaker and forms a pseudo Dark Spam core with Mega Gyara. Raikou is the necessary Thundurus switch in, and I went with Toxic for the Hippo switch ins. Gyara covers most Ice-types, so I went to with Sub SD Chomp, who equally puts pressure on offensive/defensive builds and can check electric types occasionally. Latias and Metagross are the support. Defog isn't essential, but it makes using Gyarados a lot easier, especially late-game (if I'm lucky enough to get off both a Defog and a Healing Wish) and makes things against the uncommon Mega Venusaur easier. Metagross is my Fairy switch in, Rocks setter, and the only member of the team who can do much to Ferrothorn. These two have to perform a lot of jobs, which they do pretty well most of the time.
Some obvious issues are the aforementioned Ferrothorn. If Metagross is KO'd, I have to hope that I can boost up enough to break it down. Bulky grounds can be annoying since my main way to handle them is Weavile, who takes Rocks damage and then has to hope he's not switching into an attack. Scizor is a minor annoyance since he likes to switch in on Latias and Weavile, but the other team members handle him well. I'm sure there are other issues but I don't have the wherewithal to think of them. What do you guys think? I encourage you to play around with it; it's a fun team.
http://replay.pokemonshowdown.com/ou-394768954
http://replay.pokemonshowdown.com/ou-394766755
Sorry for short explanation/errors, I'm on my phone.