As others have said. The devs have made it clear that a real pet job will not be a thing in the foreseeable future. See SMN for more details since it's an example of such an approach.
If you ask me how I can imagine a beastmaster as a normal job, then I'll say the only way I can imagine it working without having real pets at your side would be by having each skill calling out for a different beast or something similar in that regard. Think of release but each skill is based on it.
But if it was a limited job, then it can be either a real pet job (Since balancing doesn't matter) or by taming different beasts around the world where each kind can give a different skill. Think of Bozja lost actions but you acquire it from taming beasts and add more uses to it up to its limit by taming more which means BST would probably be on the lookout for taming more from a while to another.