Trachy is redoing them. He is calculating every Pokemon's movesets on their pages against every Pokemon. He wants people to return home. D: They will probably be done in April or May (Mass Effect 3 is out soon), along with our PO server.
trachy: It personally offends me when the tiers are said to suck. So I won't have anything for people to complain about now. Come when they finish, I will have hopefully destroyed any need for changes to the tiers ever.
Wish him luck!