As someone who really enjoyed messing with Eleki in gen 8, I really don't think we're "knee deep." Tera has cost us Espathra, Eleki, probably Volc... Maybe annihilape (Rage fist would still 6-0 stall).
The thing is... that's about it. Volcarona's been contentious for months, We knew almost certainly Eleki would be broken from the jump, and Espathra and Ape didn't take too long to be discovered. These mons all have distinct traits that caused Tera to break them. We have:
- Eleki, a mon balanced ENTIRELY by a lack of Coverage, who gained coverage
- Espathra, a mon with the unique combo of speed boost + stored power
- Annihlape, the only mon in the game with rage fist, who is maybe banworthy without Tera
- Volcarona, the matchup moth
I seriously doubt there will suddenly be any new mons discovered that become broken solely due to tera. From existing examples, it seems to require specific traits that would've been discovered by now.
Generally on a game-by-game basis, I agree with what a lot of people are saying about Tera placing value on a different skillset. That area of adaptability is something I enjoy, but I understand that people don't
You know this already: Eleki was banned cause it gained coverage, espathra was banned cause of tera fighting to not get stone walled by darks / tera fiery to muscle through some like kingambit with gleam after several boost, ape tera water definitely pushed it to quick ban, volc we have yet to see but is controversal cause volc pretty much *is* the epitome of tera, the mon in itself is what tera is.
Looking at other bans;
Both times, chien-pao was banned for tera reasons. Before it barely got banned mainly due to tera fighting to muscle some would be checks and tera dark to push its STAB crunch even further, now its definitely because tera stab crunch is way too difficult to deal with, without proper dark checks i.e. fairies.
Iron bundle was wall-able, check-able, until it tera'd then the calcs show it muscled past everything when factoring in its quark drive and revenge killing was a liability since even though it's glass it still could resist the hit with a tera if not nuking everything with it.
Palafin may have had more checks without tera water (cant touch dondozo but nowadays if there was more discussion i'm sure tera grass knot may have seen play), the fact it nuked anything that can't sponge a hit is part of why it went.
Flutter mane its hard to say, its physically fraily and would be easy to revenge kill with priority if it didn't do so much damage with tera + possibly defensive tera to avoid revenge killing, its basically a special kartana with piss weak defense and high SpD, only extremespeed doesn't hit it.
Out of all the currently banned uber pokemon that have been in OU,
5/9 were definite bans due to tera or had their bans happen sooner as a result of it
- Annihilape
- Chien-pao
- Regi
- Espathra
- Iron Bundle
3/9 Are debatable bans due to tera
- Chi-yu (might've been same reasoning as chien-pao, must;'ve just been too strong in general)
- Palafin (strong hard hitter, tera might've made it more potent than it really was but more likely it was just that strong)
- Flutter Mane (^)
1/9 isn't debatable it just didn't belong in the tier
- Zama
If you add volc to the mix there's an even higher percentage of mons overtuned by tera, and there's still large debate being overlooked with kingambit, dragonite, and roaring moon that could also be related to their teras.
Other than zama,
tera is always part of the discussion on the pokemon we've banned so far, not including anything that flat out never touched the tier at all such as lando-i, spectrier, etc.