I tried your team out and found some small issues, first off Mega-Pinsir didn't need all the speed and his attack is monstorus, so how about some bulk to survive some powerful super attacks. And Feint is just so good, you can't not use it on Pinsir.
Pinsir @ Pinsirite
Ability: Hyper Cutter
Happiness: 0
EVs: 48 HP / 224 Atk / 236 Spe
Jolly Nature
- Swords Dance
- Feint
- Frustration
- Close Combat
I've used Sand Rush Excadrill on so many teams I have gotten to the perfect speed number, but yours works perfectly well too if you are scared of fast scarfers.
Excadrill @ Life Orb
Ability: Sand Rush
EVs: 108 HP / 252 Atk / 148 Spe
Adamant Nature
- Rapid Spin
- Earthquake
- Iron Head
- Rock Slide
Hippowdon was perfect, best wall in the game IMO. But I used Impish instead of Sassy.
Loved the Scarfed Latias, but maybe try out Ice Beam somewhere on it. Zero Ice coverage on this team, maybe even Ice Fang on Hippowdon.
Standard Specs Magnezone, it works for a reason.
Rotom-Wash is most commonly used as a physical pivot for a reason, he's so darn good at it. So I moved some SpD to physical
Rotom-Wash @ Leftovers
Ability: Levitate
EVs: 252 HP / 44 Def / 212 SpD
Calm Nature
IVs: 0 Atk
- Pain Split
- Will-O-Wisp
- Hydro Pump
- Volt Switch
Awesome team, I love Mega-Pinsir and Excadrill. Started using it and thought maybe you could use my suggestions, best of luck! :)