This is because they are using the SRD 5.1 license. They had no choice to create their own archetypes past the one they were allowed to use. They have indicated that the Sorcerer class will be available as a free DLC, probably not at launch. Other classes would probably follow suit as DLC for sale, at least that is what I am thinking. As it looks right now, there will be 7 classes. Fighter, Rogue, Cleric, Wizard, Ranger, Paladin, and Sorcerer (later as free DLC), There will also be 5 races, Human, Elf, Halfling, Dwarf, and the Half Elf,
