This.
I have no idea whether there is a true healer shortage or if the UI is just bad enough that people just throw up their hands after a couple groups.
For full disclosure, my main is a heal spec'd sage.
Its a UI issue. The UI is horrifyingly bad for healers. Healers can actually do pretty decent damage and can solo much of the Heroic 2 content. The problem you're running into is that people don't want to fight a craptacular UI.
And Dual Spec would be great.