This year.
Rumor was that the campaign was going to center around Mars and the Void Dragon (the last C'tan to arise). JJ has recently said that people will not be seeing more of the void dragon though. So that is out the window (or was it misdirection
)
I bet it will involve Codex: Planetstrike in some way (and thus perhaps the wolves + Guard).
Maybe after 5th Ed. Or maybe it will be bumped to next year in light of the new Edition.
Anyone heard anything else?