I bet this is one of those things SE overlook in 2.0 lol. Not that it can't be fixed later, of course it can, but we have primals that are elemental based or at least seem to be so it would make sense to sort it out properly once and for all.
I think the elements in FFXIV were one of those "different for differences sake" things that plagued FFXIV form its very conception. Take this sequence of elements for example:
Yoshi P > Tanaka > Himself in a never ending cycle :P