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We need to spice up the OU metagame. OU has shrunk considerably with all the bans. How about updating it every 2 months? That way we can have a more diverse tier with fresh Pokemon. The current tier update time takes a long time.
We want a stable metagame, not something that we move up and down "because we feel like it." 4 months is the best in order to correspond with the UU tiering process.