Red Mage: The one class that will be impossible to impliment

[Krisan]

As has already been said, it's possible to still do RDM. It just might not be RDM as we're entirely used to it.
One thing to keep in mind is that in FFXI, RDM had the en-series spells.. Enaero, Enblizzard, Enfire, etc.. Which enchanted their raiper's with an elemental magic. They also had access to the Spikes line of spells - which we don't currently have in XIV. Things like Blaze Spikes, Frost Spikes, Shock Spikes, etc.. Which veiled them in an elemental magic and caused enemies to be countered when hit. We also still don't have direct spells that can Blind, Slow, or Paralyze enemies, only additional effects on some attacks that do this for a short time.. RDM could honestly end up as an enfeebling Tank, or possibly as a Melee mage - as in squishy but a high damage dealer on the frontlines.

Likewise for anyone who thinks this sounds too much like Spell Fencer\Rune Knight.. keep in mind that in spite of that, they managed to make both it AND Geomancer work somehow in FFXI. All three share a lot of principles in XI, yet play pretty darn differently.. So yeah, I'm pretty sure Yoshida and his team could cook us up a lot of different things. It's also worth keeping in mind that none of the CURRENT spells and skills or even how the system as a whole is setup is set in stone. They could honestly turn the whole thing on its head later, and make things much more interesting for every class when it comes time for an expansion or balancing update.