I think the way how Nikon handles the issue and comunicates with customers is actually the only problem here. Especially when the issue is mentioned in almost every review of the camera and so widely discussed on forums.
Having used affected D600 camera for more than one month now (bought new in March through standard retail channels here in UK), I don't think it is actually a serious problem.
Yes, there are some spots on my sensor, but they are only visible when shooting at f/16-f/22 when over-processing the images. No way I can see these on ordinary pictures unless I shoot something like dark sky at very small apertures (and then I can easily retouch them). This is nothing compared to pre-dust cleaning era where you had to tackle dust before almost every shooting session if you switched lenses on field.
I will propably eventually attempt to do a wet cleaning to see if these spots disappear from my sensor. However, at this pint I coldn't care less. Maybe I am just lucky or not sensitive enough.
If you are waiting just to hear that the problem is gone, then you probably shouldn't wait any longer. You can always return it or send it to service (aparently Nikon replaces the shutter mechanism for free and that solved the problem for many).