If I were to ever create my own D&D Heartbreaker, I would go with six classes, one for each ability score: Fighter (Str), Thief (Dex), Ranger (Con), Wizard (Int), Priest (Wis) and Commander (Cha). I would use talent trees feats or whatever to differentiate characters. I would absolutely NOT do sub classes. I would rather make a game with 50 core clases than use subclasses.