D3 = ID & q4 = Raven so the release dates shoudln't corelate at all.
I think that d3 & q4 both won't have very big mod communities with q2 remix on the horizon and empasis on single player. It's basically alot like SS's WFF project but with id behind it and doom3 renderer. It could be out around the same time q4 is released if raven doesn't pick up the pace.
