Divine Sacrifice was changed in Patch 3.3 to be "party only" to the dismay of many raids who now had to shuffle paladins around to groups that needed the extra protection.
I imagine in the new party-less world of Cataclysm, we could get something, like
- 30% of all damage taken by the 5 lowest health raid members within 30 yards is redirected to the Paladin...
If the goal is to make Holy Paladins be better raid healers, then I think it makes sense for them to more like Discipline Priests then Holy Priests. A Holy Paladin should be a damage shielder, redirecting damage from the raid into some mechanic that sheds the damage. Currently the mechanic is Divine Sanctuary, but The Bubble is too powerful to be on a lower cool down. Some sort of Divine Aegis that absorbs redirected damage but has to be managed carefully by the paladin.