I'm one of those red mages who really dislikes the healer mechanics we already have, so I have a bias coming into this both regarding this and using Verbatim to repeat the raise spell (I am an advocate away from the dualcast raise as it is).
As far as things to cast during invuln, Vercure 1 works perfectly fine for that. As opposed to most of the other buffs which I liked, this one adds no strategic thoughtplay into the job; it's just a spell that does what another already does, albeit better. The issue is, in order to balance for it having an aoe regen, the devs in this hypothetical would bring down RDM's dps potential, all for an ability that would be useless past world first progression really, as past that healers have all the healing needing done covered.
As far as their healing needing upgrades as we go further in, I would disagree. As it is, the best equivalent vercure has to another caster would be manawall, or to a melee, second wind, as that is their self-sustain. It's already a fairly potent heal for a DPS to have in the first place, IMO.
In that case, I really do like that. It creates a lot of forethought needed in how one approaches the situation, and they could approach it a number of ways to maximize their dps--it creates rewarding depth without being too punishing to the current playstyle.Yes, you could and should double VerHoly/VerFlare, but you could imbalance your mana so you want to set yourself up for that by being 100/88 and porpotional below to 92/80.
Now to the crux of the issue...we should be trying to move away from rez mage, not toward it. Being able to dualcast verraise verbatimraise every 15 seconds...would be truly broken. I could and do support the idea of using it as a mobility tool and the ways in which it could be used to add complex rewards to the finisher, as well as more "The Floor is Jolt 2."The cool down of 15 seconds lets you give it other uses like a second raise, another VerAero or VerThunder to help build or when you really have to move and dont have a dualcast or a Swifcast.
EDIT: I don't mean to sound overly harsh or anything. I genuinely like some of these ideas; enhanced accel, verbatim, and equipose would all, imo, be really good moves forward for the job. As I said a bit earlier in my post, I'm a bit biased; I know the history this game has with jobs balanced "for safety", PLD 3.x and WHM 3.x suffered harshly in the endgame because they were there for safety when the community values "The best defense is a good offense."