Will WHM be getting a new trait to replace ProShell?

[Cynfael]

This would be horrible. It would make it pretty unreliable.

The worst part is that players who turn up their noses at Coil would never notice the issue since accuracy requirements outside of end game tend to be very low.

I'm betting on the spell being auto-hit simply because SE might be pressured to address healer accuracy issues if the general population started noticing their shiny new spell whiffing on this new, supposedly more challenging open world content in Heavensward. Less work for them just to waive the hit check unless they already have plans to give healers the choice of quest/drop gear with accuracy as a legit secondary.