I've been lurking quite a bit in this thread and the PR thread as I usually do so I'll put my thoughts here on Tera Blast, trying to be as good faith and objective as possible.
In my opinion, an ideal metagame would have Tera Blast banned. Not for the reason of unbanning other Pokemon, but to help with threat saturation by reducing the high variance in options Pokemon have especially through Tera Blast. By reducing the amount of super high variance you make the game more competitive as more outcomes become manageable so long as you are skilled enough. However, per the tiering rules bans are done for three reasons
1. Over-Powered or Fundamentally broken, think SD Arceus Normal or on a lesser scale Annilape.
2. Uncompetitive/RNG, this is pretty simple to define, Kings Rock and Sand Veil is a good example
3. Unhealthy-ness, this is decently vague but its things that do not add to the game in a beneficial way that can or should be realistically limited. For example Sleep, and Shadow Tag fit this description. You can argue Sleep is both unhealthy and uncompetitive though, and Shadow Tag being Over-Powered too as not every ban is just 1 of the 3 reasons.
However this is mainly for Pokemon, moves are a bit of a more special case and are much more strict for tiering. The reason for this is deter Tiering to be move based, where you balance Pokemon by banning moves which can quickly become a slippery slope.
Looking at this it's obvious Tera Blast isn't Over-Powered, and it's certainly not RNG functionally speaking so you'd be arguing on it's healthiness for the game along with how realistic limiting Tera Blast is and the universalness of its unhealthy effect.
First, the reason why limitation is a factor is you can't just ban every little thing that goes against smogon principles because of logistics, how can you ban Paralysis without banning every secondary effect that can cause it? In the case of Tera Blast you can logistically ban it with no issue.
Second is Tera Blast unhealthy for the metagame and assuming so how unhealthy is it? Defining unhealthy for a meta is what smogon tiering values in the metagame and this is a case by case basis. For example Trapping in LC is deemed not that unhealthy as a concept due to the offensive nature of the tier. In the case of SV OU it is not a crazy claim to make that SV prides itself on it's offensive diversity and freedom. Tera Blast is a move that exemplifies this no matter which way you look at it, and while I and a lot of others find Tera Blast to push the limits and borders into 'Unfair' or 'not very competitive', Tera Blast has just enough leeway in terms of risk reward, and predictability that it is not objectively unfair. Tera Blast also fits very nicely into the confines of what the Tier is currently, and the tier has to offer and generally speaking what the playerbase wants in the tier. Would removing Tera Blast make games more competitive? I would say 99-1 odds yes. But unfortounately Tera Blast has just enough leeway that I cannot say it's strictly uncompetitive. Do I think removing Tera Blast would make the SV OU metagame more enjoyable or interesting especially for defensive play? Yes I'd once again say 99-1 odds of me being correct, but Tera Blast is a literal physical representation of high variance divsersity and offensive freedom. Even if it goes a little over the edge who's to say that's just how the tier is rather than a problem that needs to be solved? see the issue. Tera Blast is the literal philosophy of this tier, so again the reasoning of it'll make the meta improve cannot be used effectively.
And as a final nail in the coffin, moves are tiered very strictly and you're gonna need a damn good reason to convince tiering admins to ban a not universally broken move. Tera Blast isn't univerally broken so I don't think this needs further explanation.
I think it's safe to say that this is an ideals vs truth situation, Reshiram vs Zekrom if you will. Quite literally.
In my opinion it's very difficult to have a good faith argument that Tera Blast is good for the game besides further enforcing a questionable status quo. However with the ruling set in place on how to tier, Tera Blast action just doesn't make much sense either. It boils down to do you prefer following the rules and listening to the truth on Tera blast or do you want to create an ideal sv ou even if you trample over a few rules for a desired outcome. Personally I'm the latter but this is an opinion. For me I think when we can make the game better in a non intrusive way we should do so. Yet I can 100% see why people are against Tera Blast action, especially TL's. Unless we wanna shake up the status quo of tiering as well as what SV OU should be (which im all for changing sv OU lol) then I don't think Tera Blast action will become a thing or make too much logistical sense given current tiering standards.
I'm for Tera Blast ban, team zekrom (ideals) and thanks for the transparent discussion council/TL's.