If you wanted to make some more console game parallels you could look at the Wii experience compared to something like Grand Theft Auto IV. While the best games on the Wii are all about the way you interact with them through the controller, GTA IV is about how you interact with the game through the story. Both experiences rely on some form of interaction, but both have their extra gimmicks layered on like a nice delicious candy shell.
Not that gimmicks are bad, but they do wear thin after a while. The real reason people continue to enjoy the Wii, GTA IV and could possibly continue to enjoy AoC in the coming months is because there is a core experience worth coming back to play. With the Wii it's how you and other people can interact with a game in a completely different way and in GTA IV it's about how the story is much more compelling than ever before. So what's the main draw keeping players interested in Age of Conan? We probably won't know for a little bit, but it could be the combat system. Then again the combat system is different for magic users, so maybe it's the overall mature Conan experience.
Our guess is that in a month or two we'll have a better understanding of whether or not Age of Conan is truly a next generation MMO or if it's just a very good one. If everyone playing the game is still having fun with the combat and overall game experience, that'll probably be our answer.