That is ok, Nikon will bring out a fix (D7200).
Nikon is being very bad to consumers...haven't had time to go through the forum sentiments...but i think that D610 and D5300 are no updates but a shameless way of fixing issues with the earlier cameras, without even acknowledging the problems. So what are the owners of the earlier iterations supposed to do?
What is the effect on the norlal use and output of the camera?
Close to none. After 2 years my sentiment to Nikon has changed a bit. They learnt their lesson and on several occasions they went public soon. Course they didn't yell "hey, you know what? We messed up again!" but they acknowledged some of the issues and fixed them.
Actually I find more and more, the "issue" is more likely the internet and everybody going public with every "strange", "weird" or "odd" thing one has seen. Some people are happier if they find something to complain than if they manage to get a nice picture, others get angry if they find a real issue. Telling others about is part of the anger-compensation.
As to the scratches, rembart never came back to answer the question "was it Nikon's mistake or did the sand grains get in because of you?" It only needs a little particle to scratch off the thin layer of coating on the metal blades. I don't exclude it happened during the manufacturing process. I just think, more likely he changed lens at the sea in windy conditions. Might be a false assumption, but rembart is a dutch name. So, sea, beach, sand, breeze are not hard to find in the Netherlands. Snince he mentioned Nikon Korea - South Korea is also a coastal country.
Worst thing to happen is dust or sand on the sensor. A good blower and some skill in sensor cleaning should do. No skill in sensor cleaning, however, could cause scratches on the sensor glass. Then things would become expensive.
Disregard JoJu's rant is my advice. The scratches are not from "grains of sand".
Whether they are a problem, I don't know. They might influence the shutter life a bit, due to structural changes, but for the rest, have not read about odd shutter failures or other problems stemming from the scratch issue.