i really think making DS cost no holy power and giving the 4pc a bonus to TV would be a better solution to the problem :/
it adds another button to use in the rotation (DS), but our main strike (TV) gets the main benefit from the set bonus.
If DS doesn't cost Holy Power, then we have no AoE Holy Power dump, and DS would work its way back into single-target rotations (during empty GCDs, if nothing else). Neither of those effects is particularly desirable, at least IMO.
But I would like to see the 4pc return to affecting TV, or otherwise not make the rotation really weird for six months.