Just a random idea. What if we change the GCD lockout (the 'recast') on some of the heal skills from 2.5 down to 1.5s? Or even 1.0s? If Regen was a 1sec mini-GCD, would it be more appealing to use, or at least, less opposition to the idea in raids when it's needed? I remember early P8S I'd use Regen on both Natural Alignment DOTs, and Medica2 as well, so I'd have felt the difference there.
This doesn't help the issue of 'well there's not exactly all that much to heal', but it'd at least maybe make 'lossy GCDs' feel a bit less punishing to use hopefully, instead of the hamfisted 'well make it damage neutral' solution that leads to weird stuff like Macrocosmos being a GCD, or Misery ending up being ridiculously swingy because of crit variance