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OU by technicality is updated every 6 months with mons that have usage far below the usual OU cutoff (has to be less than 2.28% iirc). Azelf is not there likely because, despite being bad, it's still used enough in ladder to stay in the regular OU list.
I'd say the biggest W about this is that this thread won't be unbearable to read again but I wouldn't be surprised if it goes back to dropping ubers discussion