Potencies can and likely will be adjusted for both Solace and Rapture. Whether it happens now or sometime in the future, what matters is it gives the devs the flexibility to do so while leaving Cure 2 and Medica alone. The two abilities also have an additional effect of nourishing the blood lily. You could argue that these additional effects could also be baked into Cure 2 and Medica, but they're acquired at different levels and tooltips are pretty much written in stone in the sense that they don't change as you level up. I'd also have to point back at the potential potency adjustments. They also have their own animations, which might not be your thing, but others enjoy it.

I do see what you're saying though. The afore mentioned aren't really constrictors the devs couldn't work around, but also valid reasons to have these abilities be separate. if button bloat is your concern, there are bigger fish to fry. I would look more at abilities like Fluid Aura and Repose. When it comes to raid utility, WHM is never going to get rDPS. Not in 5.0 anyway. If they ever do, it will likely come in the form of an AoE and weaker version of PoM.