At the beginning of UU, everything that is potentially broken is banned by a council. Then, each banned element is reintroduced to the tier one at a time, and the UU council votes on whether each suspect should be kept in UU or remain BL.
UU Tiering explained
Tiering in UU is a little different from tiering in OU. Some of you may remember the kokoloko system that was used during XY and early ORAS, and this time, we'll be doing things largely the same way. Here is an explanation pertaining to what the system is and why we are using it.
The UU Tiering System
As with every tier, tiering begins with the beta stage. At the very beginning of UU Beta, the most blatantly overpowered elements of UU are quickbanned by the tier leaders.
During the next stages of UU Beta, the UU council will be formed. Approximately once every week, each member of the council nominates elements of the metagame that they believe to be banworthy, and the council collectively votes on whether or not to ban each of these nominations. Nominations that receive a simple majority of "Ban" votes will be banned from the SM UU tier. This process will be repeated until UU is out of its beta stage, and by this time, everything that is potentially broken should be banned. From then on, suspects will be reintroduced to the tier individually via suspect ladders, and a suspect discussion thread will be opened to the general public. For each suspect, after an appropriate amount of time, the UU council will vote on whether or not to unban it. A 2/3 supermajority of "Unban" votes will be required to permanently reintroduce the suspect to the UU tier. A vote will also be held following each major tier shift, where council members can nominate current metagame elements for a quickban as well as new drops from OU.
The purpose of this is to create a stable, healthy metagame in the shortest possible time frame. Once this metagame is achieved, we begin to introduce potentially broken elements one at a time into the tier to see if they are truly broken or not. By using a council-only system instead of a public system, we reduce the amount of time needed to get through all the suspects and ensure that the metagame is stable at any time bar the current suspect. Once the tier is deemed stable enough to not need constant quickbans and subsequent suspect tests, we can proceed with public suspect tests.
The UU Council
For the beta stage of UU, there will be a nine-person council consisting of the tier leaders and other valued and trusted members of the UU community.
After the beta stage is over, the UU council will consist of 12 members. Nine seats are taken up by the tier leaders and their most trusted contributors, and three additional rotating seats are filled by other members of the community. These rotating members of council are selected by the tier leaders and will be reselected after every suspect round. These spots are filled by people with good contributions to recent suspect test discussions, a high level of general activity, and good playing ability. All council voters must participate in the discussion for the suspect tests they vote in.
The UU Metagame
As UU is formed, it is going to be vastly different from its past iterations. While some "staples" may remain, others may find themselves with high usage in OU or buffs that may send them to BL. Accordingly, there are few constants between generations and a lot of Pokemon will have to be reexamined and reassessed, leading to this council-based approach and the necessity of many early bans on the notion of something being potentially broken or unhealthy.
If you still have concerns because this is not the standard tiering method, let us alleviate those by assuring you this method is by no means untested. As mentioned earlier, then-tier leader kokoloko pioneered this method at the start of Generation 6, and through this method he created a metagame that was widely considered great. We hope to replicate this success and are looking forward to your cooperation. Let's create a great tier together!