Hi hi. Been playing Showdown ever since XY under a lot of different names, so my perspective comes from someone who's used to every generation introducing some brand new defining characteristic that ends up making a huge impact on the metagame. I've watched discussions about Mega Evolution and Z-Moves and Dynamax from the sidelines, but decided to make an account here finally just because I feel like this is something I should speak up on.
(tl;dr I want Terastal to be limited in some fashion like showing Tera types on team preview or only having one dedicated Terastal mon but since the only options are ban or no ban and the meta hasn't had time to settle yet I say no ban for now)
The way I see it, Terastal is something sort of in between Z-Moves and Dynamax, being incredibly flexible and built around the surprise like the former and a persistent effect that changes how you have to fight a mon like the latter. Dynamax was banned though, and I think most people (me included) are pretty okay with that. Why? Dynamax puts an extremely restrictive bottleneck effect on the game. Playing around it is completely mandatory, virtually always going to happen the same way, and its only real counter is also using it in response. The meta begins to pivot around Dynamax rather than it being a part of the meta. You can make teams without Mega Pokemon or Z-Moves and do just fine even if your opponent has one or both, but if you don't Dynamax and your opponent does, you are immediately at a huge disadvantage because of that.
So what makes Terastal a middle ground? A couple reasons, most notably in my opinion being that Terastal isn't only countered by itself. You can predict it, play around it, and punish it, albeit with more or less difficulty depending on the combination. I compared it to Z-Moves earlier because it's got a lot of flexibility, but instead of one giant hammer of a move or super big buff, you change how the Pokemon works. A lot of weak Pokemon get stronger, and a very interesting defense metagame is created of predicting what Tera type a Pokemon is, when they'll Terastallize, who they'll use it on, and how you'll respond to it afterwards, often creating a situation where whoever Terastallizes first is at a disadvantage. Unfortunately, Terastal has the downsides of also being kind of mandatory to use every match (ish, not like Dynamax where not using it was an objective and straightforward misplay) and of making already-strong Pokemon even stronger. The double STAB bonus is really strong on its own, but add in any other kind of damage buff like Swords Dance or rain... Well, you've seen the posts here about stuff like Swift Swim Barraskewda. It's crazy. On the whole, people haven't developed reliable ways to shut it down yet.
That "yet" is going to do some heavy lifting in this paragraph. Scarlet and Violet have been out for all of two months as of this post, and I just don't think that's enough time to decide whether or not this mechanic can be wholesale banned for the entire format. Terastal is not like Dynamax, where it's mandatory and has little variation and if you aren't also doing it you're kneecapping yourself. There's a lot of different things you can do with it, and even the really nasty combinations aren't immune to being checked. Of course, over time people are naturally going to settle on a few combinations that prove to be the most consistent, like Tera Normal on anyone with Extreme Speed, Tera Water or Fairy for defensive Pokemon that need to shed an inconvenient typing, the aforementioned Barraskewda, so on. But those combinations aren't the only possible uses for it, and they don't force you to use them in return. You could even argue a Pokemon having an extremely predictable Tera type makes it open to being countered, but that's not really my overall point.
Now, despite everything I've said here, I do think Terastal needs to be reigned in for the time being. In my experience on ladder at least, the nastiest thing about it is that you don't know how the opponent will use it. You don't know when they will, who they'll use it on, or what type their Pokemon can suddenly change to, which is especially dangerous when a Tera Blast comes off a Pokemon that blindsided you. The first one of those kinds of mind games is absolutely mandatory if you want Terastal in a competitive format, and not necessarily important if they plan to use it strictly offensively, but the second two are able to be extremely strong situationally and can pivot the course of matches. In my humble and handsome and intelligent and very humble opinion, we should probably start with removing one of those questions. Perhaps only one dedicated Pokemon on your team could be the one you can Terastallize, or Tera types are displayed on team preview. The ambiguity of how and when it will pop up in a match is one of the strongest things about Terastal, and selectively clearing up parts of that ambiguity might do a lot to make it more manageable. Who knows? One of these might work. We won't know if we just delete Terastal and all experimentation with it.
Also, this one's just a me thing, and I fully understand that fun is subjective and being competitive is the most important thing, etcetera and etcetera, but I think it'd be a real shame if the National Dex format ended up looking really similar to how it did last generation except Chien-Pao's the new revenge killer on the block and Tapu Koko/Regieleki shenanigans include Quark Drive users now. Terastal has a lot of really fun and creative applications I'd hate to see junked this early into Gen 9's life.
(tl;dr I want Terastal to be limited in some fashion like showing Tera types on team preview or only having one dedicated Terastal mon but since the only options are ban or no ban and the meta hasn't had time to settle yet I say no ban for now)
The way I see it, Terastal is something sort of in between Z-Moves and Dynamax, being incredibly flexible and built around the surprise like the former and a persistent effect that changes how you have to fight a mon like the latter. Dynamax was banned though, and I think most people (me included) are pretty okay with that. Why? Dynamax puts an extremely restrictive bottleneck effect on the game. Playing around it is completely mandatory, virtually always going to happen the same way, and its only real counter is also using it in response. The meta begins to pivot around Dynamax rather than it being a part of the meta. You can make teams without Mega Pokemon or Z-Moves and do just fine even if your opponent has one or both, but if you don't Dynamax and your opponent does, you are immediately at a huge disadvantage because of that.
So what makes Terastal a middle ground? A couple reasons, most notably in my opinion being that Terastal isn't only countered by itself. You can predict it, play around it, and punish it, albeit with more or less difficulty depending on the combination. I compared it to Z-Moves earlier because it's got a lot of flexibility, but instead of one giant hammer of a move or super big buff, you change how the Pokemon works. A lot of weak Pokemon get stronger, and a very interesting defense metagame is created of predicting what Tera type a Pokemon is, when they'll Terastallize, who they'll use it on, and how you'll respond to it afterwards, often creating a situation where whoever Terastallizes first is at a disadvantage. Unfortunately, Terastal has the downsides of also being kind of mandatory to use every match (ish, not like Dynamax where not using it was an objective and straightforward misplay) and of making already-strong Pokemon even stronger. The double STAB bonus is really strong on its own, but add in any other kind of damage buff like Swords Dance or rain... Well, you've seen the posts here about stuff like Swift Swim Barraskewda. It's crazy. On the whole, people haven't developed reliable ways to shut it down yet.
That "yet" is going to do some heavy lifting in this paragraph. Scarlet and Violet have been out for all of two months as of this post, and I just don't think that's enough time to decide whether or not this mechanic can be wholesale banned for the entire format. Terastal is not like Dynamax, where it's mandatory and has little variation and if you aren't also doing it you're kneecapping yourself. There's a lot of different things you can do with it, and even the really nasty combinations aren't immune to being checked. Of course, over time people are naturally going to settle on a few combinations that prove to be the most consistent, like Tera Normal on anyone with Extreme Speed, Tera Water or Fairy for defensive Pokemon that need to shed an inconvenient typing, the aforementioned Barraskewda, so on. But those combinations aren't the only possible uses for it, and they don't force you to use them in return. You could even argue a Pokemon having an extremely predictable Tera type makes it open to being countered, but that's not really my overall point.
Now, despite everything I've said here, I do think Terastal needs to be reigned in for the time being. In my experience on ladder at least, the nastiest thing about it is that you don't know how the opponent will use it. You don't know when they will, who they'll use it on, or what type their Pokemon can suddenly change to, which is especially dangerous when a Tera Blast comes off a Pokemon that blindsided you. The first one of those kinds of mind games is absolutely mandatory if you want Terastal in a competitive format, and not necessarily important if they plan to use it strictly offensively, but the second two are able to be extremely strong situationally and can pivot the course of matches. In my humble and handsome and intelligent and very humble opinion, we should probably start with removing one of those questions. Perhaps only one dedicated Pokemon on your team could be the one you can Terastallize, or Tera types are displayed on team preview. The ambiguity of how and when it will pop up in a match is one of the strongest things about Terastal, and selectively clearing up parts of that ambiguity might do a lot to make it more manageable. Who knows? One of these might work. We won't know if we just delete Terastal and all experimentation with it.
Also, this one's just a me thing, and I fully understand that fun is subjective and being competitive is the most important thing, etcetera and etcetera, but I think it'd be a real shame if the National Dex format ended up looking really similar to how it did last generation except Chien-Pao's the new revenge killer on the block and Tapu Koko/Regieleki shenanigans include Quark Drive users now. Terastal has a lot of really fun and creative applications I'd hate to see junked this early into Gen 9's life.
