After Summoner and Dark Knight, I've resigned myself to the knowledge that there will never be a job that is truly faithful to the classics. Black Mage's only use three elements, white mage's come closest but somehow gained the ability to stone enemies to death as opposed to light based spells, like Dia, which would've made sense (and were in the pre-calamity FFXIV).

Red Mage should, arguably, be the ultimate hybrid. Their weapon should be swords, with the ability to both heal and cast black magic spells. They won't be, but that's really the whole point of this. A lot of jobs are just shadows of their namesake. Whatever they come up with will work with the current game meta, so I guess we'll just have to sit tight and wait to see if it's something that we want to play as.