I was gonna write a post on how STag isn't busted but it's kinda wrong. The more I thought about it the more I realized how stupid it is in a meta like Middle Cup. The reason STag is such an issue is because of the way MC's meta works. Currently and even last gen the tier is filled to the brim with offensive threats and not enough defensive mons to check them. SuMo helped ease the issue by giving Gloom an amazing recovery move but at the same time we have Z-moves introduced making certain threats even harder to deal with.
What does this have to do with STag?
To break down the issue STag can be used in two ways, offensively, and defensively. No matter which way you use it you get the same result, your team kinda just wins. If you are using it for a more offensive team suddenly that one crucial defensive Pokemon your opponent need to beat you is gone and there is almost no counter play. Simply put the team facing STag in this situation can't risk ever knocking out a mon with anything that can be trapped and killed on the field. Chances are every Pokemon on a MC team, especially defensive ones are important and if the get eliminated before they can do their job the game is pretty much set and done. Given the right set Gothorita can trap and eliminate pretty much every fat mon (CM rest talk), anything else is either weak to it's STAB or can be taken care of after some hazard damage and a coverage move given it's running something like Scarf or Z-move. The few Pokemon it can't trap (ghosts) aren't even the biggest threats. Once Goth traps the Pokemon it needs to, chances are that one of your mons just kinda runs through their team or really puts in the hurt.
On the flip side Goth is very useful for defensive teams. Fighting-types are ever prevalent and ever so annoying to deal with. Thankfully Gothorita just kinda beats all of them. Guess what, that Chansey that walls half your team? Good luck beating it now. Even non-fighting-types need to be scared because just the presence of Goth in the back can force many doubles, given the right hazard support eventually Goth can come in on anything and just beat it.
Sure you can run Shed Shell but there goes your lefties and all that damage your Pokemon once could dish out.
At the end of the day the ability to trap everything except Ghosts and other STag users is far greater than trapping just Steel-types. And once you put it like that it seems a whole lot more unfair and uncompetitive.
What does this have to do with STag?
To break down the issue STag can be used in two ways, offensively, and defensively. No matter which way you use it you get the same result, your team kinda just wins. If you are using it for a more offensive team suddenly that one crucial defensive Pokemon your opponent need to beat you is gone and there is almost no counter play. Simply put the team facing STag in this situation can't risk ever knocking out a mon with anything that can be trapped and killed on the field. Chances are every Pokemon on a MC team, especially defensive ones are important and if the get eliminated before they can do their job the game is pretty much set and done. Given the right set Gothorita can trap and eliminate pretty much every fat mon (CM rest talk), anything else is either weak to it's STAB or can be taken care of after some hazard damage and a coverage move given it's running something like Scarf or Z-move. The few Pokemon it can't trap (ghosts) aren't even the biggest threats. Once Goth traps the Pokemon it needs to, chances are that one of your mons just kinda runs through their team or really puts in the hurt.
On the flip side Goth is very useful for defensive teams. Fighting-types are ever prevalent and ever so annoying to deal with. Thankfully Gothorita just kinda beats all of them. Guess what, that Chansey that walls half your team? Good luck beating it now. Even non-fighting-types need to be scared because just the presence of Goth in the back can force many doubles, given the right hazard support eventually Goth can come in on anything and just beat it.
Sure you can run Shed Shell but there goes your lefties and all that damage your Pokemon once could dish out.
At the end of the day the ability to trap everything except Ghosts and other STag users is far greater than trapping just Steel-types. And once you put it like that it seems a whole lot more unfair and uncompetitive.