Yes. There are tons of open, difficult rationality/philosophical problems. If they haven't 'cropped up in a while' on LW, it's because those who are thinking about them aren't taking the time to write about them. That's quite understandable because writing takes a lot of time.
However, I tend to think that there are enough very smart rationalists on LW that if we can cogently bring everybody up to the cutting edge and then explain what the open problems are, progress will be made.
That's really where I'm going with my metaethics sequence. I don't have the hard problems of metaethics solved; only the easy ones. I'm hoping that bringing everybody up to the cutting edge and explaining what the open problems are will launch discussions that lead to incremental progress.
More and more, LessWrong's posts are meta-rationality posts, about how to be rational, how to avoid akrasia, in general, without any specific application. This is probably the intended purpose of the site. But they're starting to bore me.
What drew me to LessWrong is that it's a place where I can put rationality into practice, discussing specific questions of philosophy, value, and possible futures, with the goal of finding a good path through the Singularity. Many of these topics have no other place where rational discussion of them is possible, online or off. Such applied topics have almost all moved to Discussion now, and may be declining in frequency.
This isn't entirely new. Applied discussions have always suffered bad karma on LW (statistically; please do not respond with anecdotal data). I thought this was because people downvote a post if they find anything in it that they disagree with. But perhaps a lot of people would rather talk about rationality than use it.
Does anyone else have this perception? Or am I just becoming a LW old geezer?
At the same time, LW is taking off in terms of meetups and number of posts. Is it finding its true self? Does the discussion of rationality techniques have a larger market than debates over Sleeping Beauty (I'm even beginning to miss those!) Is the old concern with values, artificial intelligence, and the Singularity something for LW to grow out of?
(ADDED: Some rationality posts are good. I am also a lukeprog fan.)