This is awesome.
But for this to be really ground breaking and useful, Voodoo nodes need to be crowd sourced, not run by CS. And they also need to change repeatedly and not be fixed for the whole session of the user, to prevent easy fingerprinting and pinpointing users' IP addresses (I assume multiple people can connect to one Voodoo at the same time or else this is useless).
Voodoos see the Source IP addresses of users, but NOT the plaintext data. Never see plaintext data since they'll always be encrypted either to or from the Core OpenVPN server.
Cores see the plaintext data (assuming no other Encryption is in place), but NOT the Source IP address (they see the Voodoo IP).
So, what these requirements I listed prevent is putting all of the user's apples in one basket (data and IP in the hands of CS staff), and of course, this will add plausible deniability for CS and distance them from some headache; and at the same time ensure that users guarantee that whoever has the data doesn't have their IP, and whoever knows their IP (the Voodoo) can't see their data (since there encrypted to and from the Core OpenVPN server).
So again, ease make Voodoo nodes a crowd efforts. Otherwise I can't see how this is any different that traditional OpenVPN setup.