First read this MMOs vs the World Part II and if you did not follow the link to the Bartle interview there read that as well.
I know I have pulled back on my gaming so that I basically play one in each genre type. Why? because like Bartle I have seen most of them before. Unlike Dr. Bartle, I still enjoy playing games, but then I do not design them for a living. That is basically where I am right now in gaming, I want something to grab my attention and suck me in, but nothing does really. Well nothing that hasn't already that is. So, yes the design DOES matter as does the game itself. But one thing that I think Dr. Bartle is missing because of his proximity to the Industry is also a coherent story. Why am I going in here and blowing away these monster? Where did they come from? Why me?
Games that have stuck with me do so because of the story as well as the mechanics and the blood fountaining in slow motion. The characters matter. I have to want to save the world. Add to that what I call the creator's fun factor. Did they have fun making this game. Are there things in there just because? What about easter eggs? Does anyone remember what Zork replied when you typed in Fuck you! out of frustration? Those things stick in my mind to this day. Maybe when gaming companies start having fun creating games again I will find one that sucks me in again. Until then I will continue to play the others that never let go of me in the first place- that is good game design!