Um i don't think ifrit, titan, garuda, leviathan, moogle mog, shiva and ramuh are elder primals, they are lesser primals iirc. The elder primals that we know of so far are: Bahamut and Odin. Both of whom where sealed away until they were freed by the calamity. Personally the primal I am waiting to be released is Phoenix, you all know you want him. They did him so much injustice in FFXI...

ALso, A fight against the elemental of nihility would be badass... I loved the whm storyline from 1.0!