A branching system such as the one I am referring to, doesn't exclude any classes. Simply to unlock classes you need to have met rank requirements with specific jobs. Example when a Conj. reaches lvl 15 and his THM is lvl 10, the player unlocks the ability to use Black mage, and white mage. When his THM reaches lvl 20, he unlocks RDM. so on, and so forth. Basically dif. job ranks meeting together to create new optional advanced jobs.