Sadly its not likely to change unless they overhaul THM/BLM, because they only have Fire/Ice/Lightning, and the devs fear something like the elemental wheel keeping people from including certain classes/jobs. They're going to keep to this little statement probably until the game sees its end.

Meanwhile, I'm sure everyone looks at the Elemental Resistances, as well as the Status Ailments and Damage Type resistances... and see all that wasted character data that could be better put towards... I dunno, another 25 inventory slots per character maybe? Heck we have 75 for Key Items... has ANYONE even had a full tab(25) of these? That's 50 available slots that are WASTED.