First!

[Horadrim]

Supposedly RNF is supposed to be better than PLD at magic tanking. I'd love to see them beat Aegis, but a new job has a lot of potential.

that said, I seriously doubt they'd put all of these useful abilities below 49. It might work marginally better than /RDM for magic dmg tanking, but they're not going to put Aegis-trumping abilities being accessable by a sub. Would kill the job long before it came out (and further screw up the balance of tanking as it is now)

I think RNF is supposed to be great at magic defense and augment Paladin as a sub. I don't realy see how else they are going to put Defense tanking back on the mark without doing something with RNF that makes them both viable. I expect RNF will do something like have a trait that converts half damage to Magic damage and allows for additional mitigation through Magic Resistance, which as a sub would instantly make both it and Paladin capable of withstanding great amounts of damage.

A trait that converts damage taken from an enemy into enmity from that enemy would be useful and logical as well -- but I've come up with "that makes too much sense for it to be something SE thought of" stuff before.

If the problem with defense right now is that it works similarly to other stats (after a point it stops having an effect) then the only real practical answer is to either fix the upper limit of Defense (which they have yet to do after years and years of knowing its a problem) or give abilities that allow you to lower the incoming numbers below those limits to increase the effectiveness -- and making RNF Paladin's equal, but in terms of magic defense vs. physical defense and then giving them an ability they can share to split the damage between the two types of defense (maybe based on whichever is higher?) would be a lot of sense.

Meanwhile, it wouldn't be useful to DNC or NIN tanks because they don't have enough magic defense to make it worth converting their physical damage to magical damage -- basically making RNF a PLD only sub.

Though, then that might open a weird door for White Mages, depending on how much you could convert.