Do you have a D600? (I can't tell, because your user profile is blank).
Nikon is unlikely to take too much notice of web complaints or petitions - simply because they have no way of telling whether any individual is being truthful. What they will (or should, at least) take note of is a complaint backed up by evidence, and/or a camera returned for service that has a clear fault.
And... Nikon have actually "publicly addressed the issue" - they made a statement that some D600's suffer from more sensor dust than one would expect, and if normal cleaning doesn't fix it, the camera should be sent in for attention.