Technically there is at least some semblance of 'light' and 'darkness' aspects in FFXIV's lore, in the form of astral and umbral elements, however, as has been stated, actual elemental aspects on spells and abilities have been removed (or at least minimized as to be practically imperceptible). Whether SE will eventually restore the elemental wheel to the game is anyone's guess though (I'd personally like to see it return, but I understand why they removed it though).