If health pools are being designed such that they typically gravitate around 60% and there is always something to heal then the distinction between increasing effective health and filling health becomes far less. I doubt we will be seeing healers taken for absorbs specifically in WoD but any situation that balances discipline and holy into different niches will certainly favour those that can flit between the two specs. That is a good thing of course, unless stat priorities remain markedly different.
We've already seen encounters that pretty much necessitate bringing someone to increase effective health (Korkron Shaman) and in my opinion that is bad design in this current healing climate. Mechanically it can be interesting, what becomes challenging is delivering information to a player that uses a basic UI. How does one show effective health if the number doesn't have a strict cap (thereby becoming health pool 2.0) and how do you show the source of such a quantity if its upkeep is essential? You could go down the Malkorok route but I wouldn't gauge that as being successful.
With such a thing in mind, I am glad that absorbs are being toned down somewhat. Discipline could very well be balanced around not having DA at all and simply creating shields through active abilities (PW:S and SS). I think this would be preferable.