Ok so ive had some time to experience the tier, laddered alot, it was very fun, built alot of teams as well but also these last 2 weeks ive done alot of reflecting, building and observing and ive come to some justifications on why tera should stay in the tier, as usual i have gathered some supporting points to not only back up my argument, but also justify why tera should be unrestricted:
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.
2. One use per game, the guessing game argument becomes invalid here because a team consists of 6 pokemon, not 1, so once a mon is tera'd, u can position accordingly, knowing they cant tera again u can capitalize on the newly gained weakness, so essentially calling it a guessing game is like saying with tera, 1 mon can win the game off the bat, which is untrue, if chi yu uses tera fighting to kill ttar, something like iron valiant can revenge and ohko with moonblast, this is a teambuilder flaw because teams need a defensive backbone, if dragonite uses tera normal, u would use the counter measure you put in place for normal types, And not dragon types.
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.
4. 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 possible weaknesses, they gonna tera to neutralise it, fairy, ice, and dragon, which means possible teras are fire,steel normal, and water, you are y side now, you know what his dragonite can tera into, you can build against its possible tera forms, 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, 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 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, breaking the boundaries and altering the proportions of the building concept altogether to something far deeper i can say with tera, the teambuilder can be limitless.
Conclusion: terastallizing is healthy to keep a competitive and consistent tier alive, since only 1-2 mons are seemingly broken with tera. And with tera, teambuilding is truely more than meets the eye.