I'm not really understanding OP's position on vercure at all.

Does it need a nerf or not? What you're proposing is to limit its usefulness, and yet you're arguing tooth and nail against how it's actually useful.

In normal use, vercure is a dualcast proc during downtime. In emergency use, vercure is literally the only way red mage can heal itself, unlike other classes which have options that don't take away dps.

I, personally, would target verraise specifically. In line with your idea, I would suggest a 50 second buff that increases all your damage by a percentage (probably low) applied upon landing Scorch. Verraise itself can only be cast while under the effect of this buff, and the buff would fade upon execution.

However, I personally don't think we should be punished for using our raise, since summoner isn't really punished for it. Any damage rebalancing we get would be baked into the class as potency changes, and verraise should turn into a gcd with a cooldown, similar to others implemented this expansion.