Every single Pokemon reintroduced to OU was only done so after substantial community support from a survey, pages of discussion, and an internal vote. On top of this, the vast majority have remained OU — even if just one or two did, it would be a huge success, but the fact that we have Deoxys-S, Zamazenta, Darkrai, Kyurem, and Gliscor (on top of different cases that are more obvious) in the tier still while multiple of them survived suspect tests is telling. Even if you dislike a few of them in the tier right now (and I’m right there with you in Kyurem), this is how tiering in a community oriented system is intended. It’s the proper way to handle it ultimately.
!dt Roost
This isn’t to mention the power creep and speed tiers around it changing a great deal + it wasn’t even banned via suspect test initially, so it very clearly was the right call to allow it if it didn’t get banned via suspect. Anything else would be abuse of power from the council.
I implore you to take a step back and look at popular teams with these Pokemon and their roles. Zamazenta is one of the best Pokemon at containing certain offensive structures — HO would be far better without it in the tier.
Calling Volcarona retest unnecessary when the community didn’t get a fair say the first time and a ton changed within the metagame is silly and revisionist history. Go back and see how things were when it was first banned. The fact that this is even a part of this post is baffling.