Honestly I don't want another single, I don't like how Castle Of Glass was used to sell a video game.
Castle of Glass is a hit single in some countries in Europe. In Austria it's the highest charting single by Linkin Park along with New Divide (both #2). And that without real promotion. I'm sure it could also be a hit in America. So i don't think COG is "abused" for a video game. There will probably no fifth single because there is still the Mall soundtrack and a new album late 2013/early 2014. But if they release one more it should be In My Remains which was the second most successful non-single when Living Things was released, right after LITE (charting at #83 in Germany, #151 in France and #10 in UK Rock Chart). Or they release Powerless outside of Japan.
Living Things really failed with singles. LITE was a complete fail. COG never became very popular. Just work on the next album and release 5 singles for it then repeat
I think it was down to the music videos to be honest, I was really disappointed that LP didn't even appear in the LITE video.
Even A Thousand Suns did better with singles than Living Things. And take into consideration ATS is a concept album.