The thing is when the Primal Focus quest was introduced all the first 3 ex primals were released at the same time. Doing it right now doesnt pose as a challenge since we're overgeared now for the new primals(excluding shiva). What they should have probably done if they wanted is just stick to the 4man story mode primals, current ex shiva, ramuh and levi would be hard mode and then release a harder ex version of them on a later patch(maybe 2.5) together with the new primal focus quest.