I like the idea of bringing Consecration back for rets as well. Having somehing unique to the spec that acts as a counter to some of the over-the-top abilities in RBGs would go along way for us. After losing the old Sacred Shield, I feel like ret has become way too vulnerable no matter how good you make our heals.
As for Divine Shield, I don't think it's nearly as good as it used to be and the 5 minute CD is not justified as it stands. I wouldn't propose changing it at all though. I think they just need to remove mass dispel from the game. It's too strong IMO.