New Caster Role Actions?

[Shurrikhan]

Not to undercut your point, but to my knowledge all of the jobs you listed except DRG and RDM have either Oh Shit buttons or mitigation effects of their own (DRG uniquely being the one to have personal vulnerability).

DRG, RDM, MCH, BRD, and DNC have no self-mitigation. NIN has no self-mitigation against 99% of raid-wide attacks. MNK and SAM each have merely 10% mitigation.
Remember, you must already give up your DPS stance and survive initially to receive the added mitigation of Riddle of Earth -- and then you have to continue to give up your DPS stance just to benefit from it, along with likely your ability to maintain GL, the core of your entire means of maintaining decent damage; that's hardly an "Oh Shit" button.

More specifically...

• 10% mitigation is FAR less valuable than a 30% HP shield. One's as good as a DRK's self-cast TBN; the other is unlikely ever to save you from an attack would otherwise kill you.
• The closest equivalent to BLM's Manaward is Ninja's Shadeshift, except Shadeshift only affects Physical Damage and thus almost never affects any damage except standing in a boss's cleave, and for does so 33% less often and for 33% less HP. BLM's Manaward is uniquely powerful.

On the whole... BLM is the only job with a decent "Oh Shit" button. And although Mana Wall was a far better fit for its purposes (as I "not moving; next hit against me doesn't matter anyways; 100% mitigation, suckers") than Mana Wall, it probably needs to be that strong to serve any BLM-related purpose.

For the record, I was only offering my interpretation of Valavaern's intent, not advocating it. In fact, I partly rebutted it -- "leave Manaward alone, give RDM its own mitigation tool."
I mean of all casters, you'd think the one to get a damage barrier would be the one that constantly runs into most enemies' blood circles.

That's fair, I guess, though I've literally never felt safer on a caster, including a healer, than when on RDM as is. Heck, though I understand the compaints, I've never even had an issue with Disengage. Just jump into Suzaku's hole slightly and fully enter Kefka's/Omega's hitbox before using it and you're always safe. I've always used it quite nearly on CD, and have yet to yeet myself off an edge even once.

No, I suspect that the only thing that's going to help in those situations is a mid-range instant-cast like Reprise that doesn't break melee combos, while the melee combos themselves cost slightly less -- allowing us to bank a Reprisal into among the melee combo if we get forced out of melee range briefly. That, or you've already used Reprise beforehand to time your melee combo to a period where no such AoE would appear... In either case, the solution isn't to give a RDM a survival cooldown strong enough mistakes or else you essentially end up giving a cooldown mean only to cheese certain mechanics, for what decent RDM would make those mistakes to begin with?

SAM and MNK's 10% mitigation skills can be kept up for large periods.

No, they can't. That's absurd.
SAM's lasts for 3 seconds and only lasts until the next hit taken. How is that a large period?
MNK's cannot be kept up, period, without sacrificing its DPS stance.

And as he also points out, Melee have higher HP as a whole than Casters, which highlights a particular weakness of RDM, the hybrid melee-caster.

Only by around 7% to 10%, though. That's a far cry from the ~19% HP increase that a Monk or SAM would need to contest a Manaward with their respective, far more costly or far less reliable mitigation.

While I understand that they may want RDM to seem more of the willowy, speedy caster, and thus its HP ought to be of no impact, I could also understand their being brought up to the HP/ilvl of, say, Ninja.

I don't want it to be a RDM exclusive because I think that defensive utility like that should be shared among the role, like second wind is.

But, again, Second Wind is approximately a 15% heal on a 120-second cooldown. Manaward is a 30% shield on a 90-second cooldown. Manaward is vastly superior in every way.
Why should one role have a skill that uniquely helps to survive against one-shots and in a single ability is practically stronger than any of the survival tools among all other roles but tanks, combined? Why? Why would you create something unbalanced? Am I crazy here for playing more than just casters, and thus looking more broadly than at their role alone, or something?