IMO,
Make Shackle Undead just called "shackle"
Basically it Immobilizes the enemy from moving and *chance* on hit to break the CC. Kind of like an Entangling Roots but for priests.
and to keep the CC for undead in place in the game, they should make it work the exact way it is now but only for undead targets.
and maybe make it an instant cast with like a 10second cooldown to get those rogues off of us
or just keep it the 1.5 second. either way i would love any change or invention of a kite ability for us priests