Constructivism represented a revolution in online learning. It changed the online classroom model from "sage on the stage" to "guide on the side" or course facilitator. What happened to online education was that the focus went from point and click online textbooks to people focusing on creating community (e.g. Paloff and Pratt). Despite that, there are people out there who call themselves "Constructivist" teachers who still use punishment and reward based learning. I think there will be a period like that with Connectivism. I do think that Connectivism will be better defined in the future and supported by research, an historical perspective, and a fully-realized pedagogy. You don't go from a single essay to fully realized idea overnight - Connectivism will have its version of "Being and Time." I think we are seeing the birth of a system of thought that will account for our new relationship to technology. Connectivism will have its different schools of thought just as Constructivism does.
The claim that Constructivism is some how vague is a little simplistic - that is like saying Existentialism is vague. There are a handful of principles one may take from Connectivism and transform a department or school -- people have.
Bill Kerr makes some good points about what Connectivism means to learning theory: There are other theories that account for Connectivism. Distributed cognition theories are over ten years old. There is a lot of re-inventing the philosophical wheel in Connectivism. Connectivism does not adequately account for social/psychological dimensions of learning (or YET account for). I think our HIM 101 class is an opportunity to create a Connectivist laboratory for working out for Constructivist curriculum and pedagogy.
There is a more philosophical account of Connectivism in one of Downes essays. The link to the version of the essay with citations is actually working so I will give a review of that article here later.