Ok so after playing a bit more in the tera metagame, ive turned into an aegislash.
I've had a change in my stance on tera, now i know i made good points about why it should be unrestricted in my last post, i've never dived into the penalties, now that i've modified my old stances, my point 1 stands from the first post as to why it shouldnt be fully banned:
1. The tradeoffs, keep in mind, if u terastallize a pokemon, even with terablast, you also change typing, which means you lose your initial typing, which means the resist that you had for the initial typing is now gone, unĺess u tera the same type which only gives u a 1.33x boost, and after gaining the new typing, u also gain new weaknesses and resistances, which can displace the balance of your team altogether, say you had kingambit for a ghost resist, and u tera into a flying type to counter fighting types like great tusk, you also gain a new weakness to rock and ice types, so stuff like banded chien pao can ice shard, and sd or ice spin on sucker if necessary.
now to the penalty:
2. You cannot predict the type of tera thats gonna come out at any turn in the game, out of over 20 types, making it almost impossible to avoid a huge difference maker, that likely will end the game if played correctly, forcing a surprise factor in every single game, and having a backbone does not solve this issue, having a backbone would only prepare u for the previous type of the terastallized pokemon, which ultimately ends in either a clean sweep, or an almost impossible position, to the ones saying having 1 dedicated tera type is the best outcome, this will make 0 difference and it does not make any sense since u already can only tera once per game, because even if you dedicate it, u still can only tera once, and u can still tera into any of the 20+ types on the pokemon you would like to terastallize anyway, since you rarely stray from a dedicated tera anyway, the game will still end on the right tera from their dedicated sweeper.
my point 3 stands from the first post aswell as to why it should not fully be banned:
3. My third point was that it neutralises the matchup concept, how many times have people lost a game and blamed it on mu? Or counter team?, tera factors this out and gives all well built teams a chance to win the game, despite the mu, so its now entirely luck and skill based and not mu based, tera introduces a new unpredictable fun dynamic which allows for exciting games and turnarounds for what seemed to be impossible or boring, it gives that momentum shift, so if say your team got leaked and your opponent cteamed u and he now has the mu, you can position your tera at x point in the game to allow for y core to have a chance to beat it, by full awareness of the sequences your opponent is making. So the matchup factor is neutralised, no one can call impossible matchup or blame it on that excuse.
now let's discuss more penalties to unrestricting tera:
4. u can apply tera on any of your 6 pokemon(including defensive ones), so on the defensive side, say u have such an uncompetitive wall like garganacl, that only has limited counters, and checked by those counters, it can easily terastallize and neutralise all of those counters and just salt cure protect spam, and all of a sudden your entire team is chipped to a game ending situation, example: garganacl vs kingambit, kingambit can iron head and kill it, but if it terastallizes into fighting or water, it can eat the hit easily and irondefense/body press, and just like that your breaker is down. example 2: garganacl vs iron treads, treads can eq right? kill garganacl maybe?, nope, terastallize into fairy. Tank eq, salt cure protect, and poof, garganacl has 1v1'd iron treads. so on offensive examples, if u dedicate a tera to dragonite, but you have chien pao on a team, dragonite doesnt need the tera, and now chien pao can use it vs a different matchup, and it will vary with matchup and give the scenario of forcing huge progress to a game ending position.
5: gameplan shifting/forces u to re-strategize: lets say u strategise vs a team on preview, and lets say u plan to spin on x turn, but what if u dont get the rapid spin off?, lets say one of their walls are tera ghost like great tusk, u wouldnt know until it teras and if it teras on your spin and kills you, your game plan is up in smokes. lets say u plan to chip this tusk with close combat into aqua jet range, but it clicks tera flying, and resists your cc and kills you, and now youre out of jet range, and all of a sudden you find yourself re-strategizing.
Let's now dive into my point on why it should NOT be outright banned:
6. The only 2 valid justifications for an outright ban is changing the outcome of games despite you knowing their tera, and changing the outcome of games due to stab tera types, addressing both we know that unpredictability is no longer an issue, since you know the effects and the tera types, now lets take a step back, what if held items came out in gen 9 and not in gen 2? There are hundreds of items that can drastically change the outcome of games just like there are many tera types that can change the outcome of games, now we know the effects, lets take some examples, we can use a team of 6 scarfers and auto win because of the surprise factor, same with 6 life orbs, and 6 assault vests, u can use any unexpected held item u want to surprise your opponent, and win because of it, does that mean this is also uncompetitive?, i did not think so, just remember a double standard is applied here, and we cannot say its because items are balanced because we did ban bright powder and king's rock didnt we?, right so, we can ban the very very few broken mons with the now visible tera types that are still pushed over the edge like chi-yu and garganacl. Concluding this point: if we want an outright ban on tera, we have to have an outright ban on ALL held items period because it is now the same impact given the best possible restriction which is show on preview.
My final point which is a modified version of point #4 in my first post, balancing the pros and cons of terastallization in a compound point:
7. (i) You have a new layer of preparation which can enable more strategising on preview on the possible outcomes of the game, now that you are aware of their teras u can begin analyzing which offensive mon can tera and plan against both those types, and which defensive mon can tera and plan against both those types aswell, for example if x pokemon is fire type, you usually would send a ground/water to check it, but if its tera is grass, u can have your ice/flying type on alert now that you know, which trains your awareness in games, because now you have to be ready for a terastal that you already know which removes the highly uncompetitive unpredictability of it, now games can only end on your lack of awareness, because you know the type beforehand, so this bends the proportions of preparation in tournaments, and gives a new light to prepping which people neglect, its always the boring part and the replay gathering, now u have this new layer of tera sheets, so u can scout what teras x person likes/dislikes, and what teras u can use to prepare against it effectively, lets see some great examples, lets take goat user giannis, he uses well structured teams and i would expect his teras to be structured too, say he likes ice teras alot for ice shard priority, u can build against it, and use resisting teras like steel and water on your ice weak pokemon, example #2, say he uses tera ghost rotom-w, there are instances where u can force that tera since it needs it so often lets say rotom-wash is the water resist on x side of the field, and u have a dragonite rain, you know rotom always tera steels/ghosts vs dragonite if it dds otherwise it loses, once you dd, you force it, now all of a sudden your water types look good since you forced their tera on the resist, now the water stab is looking good.
(ii) It twists and bends the proportions of teambuilding giving it a new layer which allows for your cognitive abilities to enhance even more, so now this layer is to balance the typings and weaknesses of your team post tera of all pokemon in the tier, lets take dragonite for example, we can take logic here lets use x vs y, x side has dragonite, you know its weaknesses, they gonna tera to neutralise it, fairy, ice, and dragon, which means teras on the sheet would be fire,steel normal, and water, you are y side now, you know what his dragonite can tera into, you can build against its tera forms now that you can see it on preview, so you have iron hands+ corv, iron hands successfully takes on dragonite's normal , water, fire and steel tera, and corv helps vs steel and normal, so we're moving back to x side now, dragonite teras into fire, now we can have a water resist like rotom wash to pair with it, since fire is the new weakness, so you can adjust your cores to benefit your team post tera given you have the tera sheets on preview, it gives u the idea/dynamic that u can build a team that can switch its offenses/defenses to other positions, this gives more teambuilder variety and ultimately never-ending cores, so the tier would never get boring it would be forever changing, so examples, tera fairy dondozo, u have a team with almost no dragon resists, tera dondozo, and now u have the ultimate dragon resist, and u can build around it as if u had a fairy like clef, example 2: tera dark chien pao, dual typings can be consistently used without compression, u can have an ice type since chien pao changes to dark, and ice can be your ice resist like cetitan, and chien pao can be used as your ghost resist, example no. 3: chi yu, tera fire chi yu makes u lose the fighting weaknesses so u can have chi yu + chien pao with only 1 fight resist, since chi yu drops its resist post tera.
Concluding this point by saying u can strategise more precisely based on the tera sheet given on the opposing team, and u can have double layer teams manipulating tera movesets to shift playstyles from balance to BO mid game, which allows for shorter or longer more exciting games that no one would know the direction till its over, and with the tera sheets, teambuilding and preparation in tournaments can be limitless.
My conclusion that my supporting points above justified:
Tera should stay, but it must be restricted, my precedence is as follows:
1. Reveal Tera type at team preview
2. Outright ban
3. Only STAB Tera types allowed
4. 1 Tera user per team
This is my final stance on terastallization.