If you look at the development notes, it says that summoning and npc taming will be included in 2.0, alongside some new jobs.
Sounds like Summoner and Beastmaster to me.
It also mentions that you will summon Primals. Which is currently just Ifirit, but will soon be Moogle, then Garuda, and eventually Odin. Probably includes Leviathan too, since they have concept art for it.