There's no reason to add any more classes when the three we have nicely cover all the expected archetypes in an experience like this. Warrior, Wizard, Rogue, can't go wrong with those options. If you feel an archetype isn't being represented well, adding additional focuses for a specific class is the better solution. This being said, the alleged exclusive content that Playstation users will get will certainly not be anything as fundamental as a class or focus.