Cleaning is to be expected but cleaning every couple of hundred shots would be unworkable for me - decide for yourself if this applies to you. I could do an occasional clean only and if that doesn't sort it out long-term the camera would have to be returned. I wouldn't return it without trying to clean it, the pattern seems to be that a replacement is unlikely to be different.
My concern is that the presence of internal debris is an indication of a problem elsewhere within the camera, and wiping the sensor isn't going to fix that. My budget means that I have to think of resale value which is difficult to predict at the moment.
And for those people who maintain that there isn't any problem whatsoever, wouldn't Nikon PR have stepped in by now to make the smallest of statements to that effect?
Despite months of misgivings I'm probably going to go ahead and buy this camera, from Amazon as it gives you a year to return if necessary and by which time a fix by Nikon might be available.