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So, if I read an opponent and they read that read, then it means I got outplayed. If I read their Tera type wrong, then I just got caught by something I didn't expect.
If they have a Tapu Fini in, and I bring in a Pex to counter it, but the end up being the Taunt CM set, is that uncompetitive...
That's not randomly changing type, that's someone choosing a type that covers a weakness for their team, and using it strategically.
If we went for that solution, a better idea would be the first turn its out, resetting when it swaps, or just not allowing Tera+setup moves.
I disagree that the mechanic is broken at all. At worst a few mons are able to really abuse it, while it just opens up the level of creativity in teambuilding and sets a lot. It makes a more diverse metagame, which is healthy for the game.
It's fairly easy to read when someone is going to Tera...
As I've been playing more, and reading more posts on this thread, I've come to the conclusion that Tera is balanced, and a few pokemon are busted with it.
The best solution I've seen is banning Tera on certain mons. Not like the "OU mons can't use it but UU mons can" type, as that has the issue...
Or you could Tera that Loom set and Terablast it to kill with fire. If you've already used your Tera, then you got yourself backed into a corner by a bad play
Terastalizing your Corv out of the situation comes with unique downsides, like not being able to Tera anything else, and possibly lose because of pulling the trigger at the wrong time.
Limiting it to STAB only is the worst solution, next to banning Terablast. Banning Terablast does absolutely nothing. There's like 2 mons that use it. Limiting it to STAB only guts the defensive counterplay to stop the megaSTAB Tera gives. Worst solution.
The Breloom situation sounds like you let a cleaner get in a position to sweep you, and lost because of it. That Breloom could also Terastalize and use Tera Blast to kill as long as Sucker doesn't come out. Unless you used your Tera too early. That play wins you the game unless your opponent...
You could've sacked a mon to give Kingambit a power boost through his ability, or run an offensive Tera for him, or run an Unaware tank to block setup sweepers.