Pixies & Titania used a lot of Rune Magic, maybe this might be the excuse to have Rune Knight in FFXIV?
I know Rune Knights would just be Melee DPS version of a Red mage with some variations, but Rune Knights are such a cool job.
And as the job levels up you can learn higher abilities in some kind of Ivalice setting (since a lot of the abilities a Rune Knight would be known for was from FFT)