I think that they are trying to make Retail more like Classic, but need to do it through borrowed power to actually do it.
Sound crazy?
Consider this: in Classic, to make any significant changes to your character takes both time, effort and resources. It’s quite difficult to change your character from raid to raid, let alone fight to fight. This instills a degree of permanence in just about everything.
And as inefficient as it is, there are a lot of people who actually like that kind of unlocking style. They are a Retribution Paladin, not a Paladin who happens to be speced as Retribution.
I think that Blizzard sees that and wants to put that element of permanence and unlocking into retail, but the genie’s out of the bottle on those things. Undoing them would cause massive player revolt.
So instead, they’re trying them out with borrowed power. Testing the waters to see if it is something that retail players will be interested in as well.