Very good point about sociopathy (and I liked the link on ethical injunctions). Many sociopaths are extraordinarily prone to self-deception. I do think that a good awareness of happiness research is important (e.g. diminishing marginal utility of additional money/power/social status - there is a point where giving things to other people increases your own happiness more than keeping the rest of it to yourself), but much of the happiness research doesn't even apply to sociopaths because their sources for happiness are different from that of others (and often in a way that makes their happiness more of a zero-sum with the happiness of others).
As for the sort of discussion on sociopathy that I'm imagining, I'm mostly imagining an open discussion. I think sociopathy is quite interesting for rationality because sociopaths have utility functions that have landscapes quite different from the utility function landscapes of neurotypicals. I've also often regarded sociopathy as a particular case where some sort of intervention may be justifiable (if we found genes predisposing people towards sociopathy), and I've often thought of what people would think of that (even though I'm very much skeptical of any intervention for genes that correlate with many other mental conditions like ADD/depression/Asperger's, which often predispose people towards increased differential susceptibility)
So I randomly ran across a very interesting site about sociopaths. The links at the FAQ and informal test are particularly intriguing (especially since many of us score lower on all 5 moral dimensions measured at yourmorals.org, although many of us would score higher if a liberty dimension was added). Sociopaths often get a lot of flak, and a lot of this flak is completely understandable, since sociopaths often effectively destroy the perception between malleability and effort (since their personalities are effectively immalleable, and no amount of effort, expressed traditionally, could help them - although I do believe that there are highly creative solutions that could integrate them better in society where they won't feel like they have a need to constantly take from others) - and people who do believe in the correlation between malleability and effort often do end up more able to change themselves. Sociopaths also effectively reduce the trust people have with everyone else - because anyone else could be seen as a potential sociopath (the possibility of sociopaths forces people to use "tit-for-tat" as the default strategy for dealing with others, rather than the "altruistic" strategy - but people often end up becoming even less generous than "tit-for-tat" due to their overreactions to negative experiences). At the same time, I was quite struck by how many of these traits (expressed in both links) also correlate with traits we see in the highly rational (as sociopaths often lack much of the emotional baggage found in neurotypicals). Of course, there are the dysfunctional sociopaths who are truly dangerous for society at large, and the more functional sociopaths, who can appreciate (through some highly creative arguments - I've used some of those arguments on myself to reduce my adolescent anger towards humanity - but it's hard for people to really think of those arguments unless they've gone through a similar phase of anger themselves) that the world does not revolve around their lives.
In particular, I found the linked sociopath test to be intriguing, since I fit all 12 of those traits (except for possibly the trait about embarrassment). The first observation was particularly interesting: "1. Sociopaths typically don't smalltalk about themselves as much as normal people do. They will direct the conversation back to the new acquaintance as much as they can." This seems like the perfectly rational thing to do (in most cases), since people generally love to talk about themselves, even though you probably benefit most by having them do most of the talking (since you learn more about their potentially informative experiences than they learn about your potentially informative experiences).
I don't consider myself a sociopath, however, since I'm still very capable of feeling shame and remorse when I've actually managed to hurt someone (although it took a lot of time for me to develop that), and I've also become a near-vegan (since I do love animals).
I think an honest discussion on sociopathy on LessWrong would be interesting.