Also, I would argue that Frederick is still good by the end of the game (as all Oifeys are). Even if one were to only level him to 20 and never reclass, if my math is right, his average stats would still be HP: 48, Str: 25, Mag: 3, Skl: 22, Spd: 19, Lck: 13, Def: 24, Res: 3, Mov: 7, which is hardly useless.