RTM
At first, your request for me to build with Mienshao was a great challenge. The mon is not good when Urshifu exists. However, I asked myself, "What does Mienshao have that Urshifu doesn't?" Well, it doesn't care about small chip like hazards, weather, and Rocky Helmet because of Regenerator, and it is faster. This led me to believe that a Choice Scarf set was Mienshao's best chance at doing something distinguishable from Urshifu. However, 9 out of 10 times, Mienshao will leave you asking yourself, "Why? There are so many good Pokemon in SS OverUsed, why did I pick this weird cat dog thing?" Wow, it's a Mienshao.
Importable:
This team takes advantage of all of Mienshao's positive traits. It doesn't care about weather, so we run sand. It doesn't care about hazard chip, so our removal can be something less consistent, in this case, Choice Band Excadrill. It likes being fast, how about we make it our speed control when Sand isn't up? You'll notice that this team is pretty much just an amalgamation of "Generic Good SS OU Sand" with bits and pieces taken from a bunch of teams, but Mienshao makes it "special" (I guess). I take no credit for the sets.
The star of the show, the Mobius of the Loki, the Lightning McQueen of the Cars, Mienshao is the team's speed control and fast pivot, inhabiting a sort of tweener role between Dragapult and Urshifu. The most notable thing about it is that it can pressure Dragapult with an OHKO from Knock Off, making it a somewhat OK thing to lead. The extra Speed over, say, Choice Scarf Urshifu, is really nice sometimes, letting it beat hail (which this team already does) and random stuff like +1 Volcarona and Nihilego. Stone Edge I think is better than Poison Jab specifically for Volcarona, and it can also lead to some surprise KOs, having a 50% chance to OHKO max HP Tornadus-T. All in all, just a mediocre mon doing its best.
Mienshao's little helper and best friend, Excadrill gives the team actual breaking and sweeping capabilities. Because Mienshao doesn't care too much about hazards, Excadrill can kind of get away with a Choice Band set, which lets it do some obscene things like OHKOing Gastrodon. Mienshao often will force in stuff like Clefable or Toxapex which Excadrill can absolutely munch on. It is also the team's main win condition, so play carefully with it.
Mienshao's teacher in how to perform in OU, Tyranitar gives the team sand, a Ghost resistance, and a Psychic immunity. We are running Choice Band here because we need a means to break Corviknight and generate actual, meaningful damage for Excadrill. Fire Punch and Ice Punch cover the most ground, landing big hits on stuff like Ferrothorn and Landorus-T. Fire Punch is particularly good for having a consistent move to 2HKO Corviknight with.
Mienshao's kinda friend but not really just some guy it knows, Ferrothorn gives the team a much, much-needed answer to Weavile. It also gives the team Stealth Rock and Knock Off support, which is super helpful for chipping things into range of a
Excadrill Mienshao sweep. Power Whip is necessary because Tapu Fini exists, so if you face one, make sure to keep your Ferro alive and well, as Rotom-W just isn't enough for Tapu Fini. Ferrothorn is also the team's best Melmetal answer, but you should also scout it Tornadus-T for Superpower, and Rotom-W is also a good backup option for this.
Mienshao's supportive buddy, SpD Rotom gives the team a secondary Melmetal answer and a general slow pivot, which is exceedingly helpful given Mienshao's terrible bulk. It also is the team's only real way to deal with bulkier Dragonite sets and is very nice for stuff like offensive Garchomp which might scare Ferrothorn away. Will-o-Wisp could be swapped here for Thunder Wave, which hits some notable stuff like Clefable, or even Toxic, which is great against Zapdos, it's really up to you.
Mienshao's idol, Tornadus-T gives the team a means to deal with all Kartana under the sea (grass? road? weird dojo?). It also performs the role of actually switching into Dragapult (shocker) with Assault Vest. Knock Off is nice for Mienshao and Excadrill to sweep later, U-turn gets our big three Choice item users in, and it's always nice for sand teams to have a very consistent Corviknight switch. It's a Tornadus-T, it's pretty much always gonna be good in SS OU.
Threats:
There's always a Chick Hicks around to ruin the show, and that is actually quite a few things for this team. Blaziken is not allowed to set up; you have to play exceedingly carefully around that mon because +2/+2 Blaziken essentially just wins. Zapdos is very annoying, as our Ground-type loses to it, so if it carries Volt Switch, you may need to make some hard reads. Just general balance is tough, Clefable as always is gonna be hard. Perhaps the biggest threat is Life Orb Low Kick Weavile, cause that essentially gets a KO every time it touches the field, and if it gets to +2, you just lose! But, this is the price we pay to use our shao-y boi.
Conclusion:
Now you may ask, why all the Cars references? The answer is quite simple. Cars is a fuckin goofy movie, just as Mienshao is a goofy ass choice to use in SS OU. Have fun, and drive safe.
Replays:
https://replay.pokemonshowdown.com/gen8ou-2016028739-p5e8l0tnizplp8fb8rsrutek3kbgdwkpw vs. Ikaishi (sorry, brother)