Well, this is what I'm thinking, actualy, of simplified game tiers:
A: Shen, Kyo, Kensou, Mr.Karate, EX-Iori, Iori, Chin, Andy, K', EX-Kyo
B: Mature, Billy, Clark, Elisabeth, Ryo, Takuma, Saiki, Duolon, Maxima, Kula, Benimaru, Joe, Hwa, King, Yuri, Leona, Athena
C: Kim, Ralf, Vice, Terry, Raiden, Ash, Mai, Goro, Robert
(no order in chars... only indexed by level A/B/C...)