The majority of the time I need to use it isn't because of a boss rotation or mechanic. Its cause my healer didn't get a heal off or healed the wrong person or is dpsing instead of healing . You can't predict something like that.

Also take this into consideration, when I use RoH as a monster is running from me I sometimes get the animation played, but no damage is done, no str down debuff applied, no gcd initiated. In short the effect was canceled out and I was not penalized for it. Why is hallowed ground any different? If it goes on cool down I should be invincible. Didn't use it in time / animation time problem? Fine, but if that is the reason I died my skill should not be on cooldown.