I was in the belief that Shiva and Ramuh were meant to be added in 2.3, with their respective hard/extreme versions. Coulda sworn they said that fairly early on... like in one of the live letter's for 2.1 i think. Would't be too far fetched though as:

2.1 - Ultima HM, Garuda EX, Titan EX, Ifrit EX, King Mog HM.
2.2 - King Mog EX, Leviathan HM, Leviathan EX

So 4 new primal fights would not be out of the question, especially on a CT patch. (although, to be fair CT was practically done before release, giving them more time to work on primals etc for 2.1)