Personally I think that the 66%+1 super majority vote might not be enough. I might be wrong on this, and would have to change my mind on the results it would yield, but I'd almost prefer a supermajority vote of 3/4, or 75%+1. The reason I bring this up is because there needs to be a clear distinction between what is simply overpowered and what is definitively broken and needs to be banned. Threats that are broken are typically more than just controversial, and are usually apparent to most if not everyone. There's a lot less room to debate over it. Shaymin-S for the time it was available is a perfect example of this, receiving 100% of the votes. I do believe we've had similar results before with suspects like Darkrai, though I don't recall the exact numbers. Another reason I feel this is ideal is because with the threshold being higher, it means that suspects are likely to stay around longer. The benefit to this is two-fold. It gives the community time to adapt and deal with the specific threat, find counter-strategies or ways of handling it, and coming to a more conclusive consensus. The other benefit is that if it doesn't reach the supermajority vote the first time, but is problematic, it will become more apparent as time goes on and is much more likely to receive a much more definitive vote the next time it is assessed by the voters since there will be pressure to remove it from the tier.
Banning is a serious last resort option, so it should require a significant number of votes. Maybe 75%+1 would be too harsh, and I'm sure some people reading would feel that way for sure. I'm uncertain too. But I do think the number could be higher than even 2/3 or 66%+1.
Is there a consensus on how the previously banned Pokemon, like titled legendaries, will be treated once we have X and Y on simulators? Will some/all of them be available in OU the way we handled it in Gen V? I have suggestions for how that should be conducted.
Based on my research, everything that was voted Uber during BW2 would have had to be retested because they didn't reach the 75+1 super-majority. Kyurem-B would not have been unbanned (yet) and the only pokes that would have received another test run back in BW1 would be Blaziken and Excadrill. Also, Aldaron's Proposal would not have passed with the super-majority and there would have been an ability suspect round. I think the 75+1 super-majority is too much but Aldaron's Proposal has been very controversial and Blaziken, Excadrill, and Kyu-B have all been asked to be retested numerous amounts of times so I do these results rather interesting.