Hi - I have this issue as well with my Nov 15 gold Macbook, and I am so, so frustrated in trying to get it resolved. My 'S' key is the worst, but several other keys are also starting to go. I haven't done anything differently with this Macbook, and have been so careful looking after it.
I reported the issue to Apple when it was 7 days out of warranty (typical), and at the genius bar they said it was a cosmetic issue, and not functional, so they wouldn't do anything. The guy there was really unhelpful and unsympathetic to the issue.
So, I took it to John Lewis (where I bought it), and it got sent off for repair under their warranty. I've just heard back that they also won't do anything as they say it is a non-functional issue - purely cosmetic. When I asked how to prevent it from happening - the guy at John Lewis said I should buy a keyboard cover, and when I mentioned that it would soon be impossible to see the letters, he said to put some stickers on the keys. He also said that if I was blind there would be no problem!
I have had many Mac computers, iPhones, iPads etc... over the years. And this is most definitely not the expected quality or standard I would expect from Apple. I could have bought a £300 laptop, and the keys would still be visible.
This is the first time I've been frustrated enough to ask for advice or support on the forums, and I feel this needs to be shared wider in case others are also having the same problem.
Also, I've been told that you have to replace the whole keyboard on the Macbook, yet I've seen information on the web that it is possible to replace certain keys - can anyone clarify?
Not sure where to turn to now.... Anyone had any positive experiences/resolution?