So me and
Miyami~~ were having some battles in Middle Cup today and we discovered a few things. One of these things is that Shadow Tag Gothorita is actually insane. I've been running a CroGoth set and it basically punishes the opponent for using slower passive Pokémon such as Chansey and Marshtomp by coming in (usually through U-Turn or Volt Switch by a mon that is checked by these defensive Pokémon), easily setting up on them, and then eliminating them and breaking down the opposing team, sometimes being able to just sweep thanks to +6 Psyshocks killing everything and it's impenetrable special bulk after Calm Mind. We think this is quite unhealthy as it can make the opposing player just autolose just for having these bulky Pokémon, which is often needed on a MC team due to all the offensive threats around. While you can potentially answer Gothorita after it has trapped something by using a Dark-type or Doublade, or just really strong physically offensive pressure, it still doesn't dismiss the fact that it can eliminate your defensive backbone in one fell swoop, leaving your team open to a myriad of offensive threats. As such, we think a ban on Shadow Tag is needed, as Gothorita clearly isn't broken without it and the ability is the problem due to it being inherently unhealthy in the meta.
Some replays showing Shadow Tag's unhealthiness:
http://replay.pokemonshowdown.com/azure-gen7ubers-115365 (Gothorita easily sets up on Mia's passive team and while it is forced out once by Haze Dusclops, it easily just comes back in and sets up again for the win.)
http://replay.pokemonshowdown.com/gen7ubers-526197734 (Gothorita comes in on Marshtomp, eliminates him while setting up, and while Sleep Talk rolls ended her time, she still left Mia's team without a defensive backbone, and making her team weaker to the Electric-types on my team.)
http://replay.pokemonshowdown.com/gen7ubers-526202807 (Goth doesn't actually do much here as Marshtomp was already dead, although this does showcase a flaw of Shadow Tag: not being quite as effective versus offensive Pokémon, so you can take that into consideration.)
http://replay.pokemonshowdown.com/gen7ubers-526205581 (The same deal here, but with Gothorita being awake, it's able to more reliably take out the other threats on Mia's team and just sweep due to it's bulk.)
I'd also like to address another topic. As you can see in the last two replays there, me and Miyami were using two non-Middle Cup Pokémon, Castform and Minun. Now, one would ask why? Well, this is because we have an idea that could help improve the meta! Right now, Middle Cup is extremely unbalanced, as you can really only use offense or bulky offense with some pivots due to all the offensive threats around in the meta. It also has a very small number of mons, and other around half of them are even good, making teams not very unique. Me and Miyami thought that maybe adding more Pokémon to the meta would spark more variety in teams, and potentially make the metagame healthier as a result. We decided that perhaps we could take some of the least-used PU mons (not fully-evolved but ones that cannot evolve such as Minun or Dedenne) and put them into Middle Cup and see what would happen. For this session, we decided to test out Castform and Minun, as the latest PU usage stats from ORAS showed them in the bottom 5 of used mons by PU usage. As these replays showed, they both weren't overbearing, as Minun mostly just pivoted around with Volt Switch and Castform died by Thunderbolt from Electabuzz or posed an actual threat to my team with a Z-Rain Dance set, KOing my Marshtomp with Weather Ball and crippling my Golbat with Thunder and paralysis. While these two weren't spectacular, we feel that they could add something to the meta, as Minun is unique in being an Electric-type set-up sweeper with Nasty Plot and a good Speed tier, and Castform has really good coverage and decent power with Weather Ball. While doing this does break the rules of Middle Cup, I think that potentially making the metagame more healthy and unique is a good payoff.