CmdrTaco has been trying to leverage crowd wisdom for years with his comment moderation system. I think a key problem is that he dosen't use a big enough sample size. It only takes a few people to moderate a comment up to the highest level. The rules of crowd wisdom state that the larger your sample size, the more likely you are to arrive at the "correct" answer. Granted, with something like a story comment, there is no "correct" answer, only interesting and relevant responses. CmdrTaco's goal was not to tease out the interesting comments though, it was to filter out the irrelevant and wasteful spam.
In essence, CmdrTaco had no choice. Spam was starting to choke slashdot comments and making them less than useful. The moderation system saved the comment system, but didn't, as many people assume that it should have done, make the comments more interesting.
I believe that if the prevailing attitude among slashdot developers is to "weed out the spam", we'll see a slow decline of slashdot's popularity until it's made irrelevant by RSS feed aggregators.
IMHO, the attitude *SHOULD* be to exploit slashdot's major differentiator over simple aggregators, which is the community it has created. In other words, they should invert the "weed out the spam" attitude into a "make the comments more interesting" attitude. It's a subtle difference and, on the face of it, it would appear that one begets the other. I contend that weeding out spam does not make comments more interesting and conversely, making comments more interesting won't weed out the spam. Thus we come to the root of the problem, two crosswise goals.
CmdrTaco has to worry about the system from a performance standpoint. Weeding out the spam means less bandwidth and storage costs. That's immediate ROI, and a good thing on many levels. The community, however, needs more than 1,2,3,4 or 5 to determine what comments to read and which to ignore, to make them interesting. I can conjecture at a few ideas that would make it better, but I do not know the ultimate solution, and I doubt anyone else does either. I believe the problem requires more than just CmdrTaco playing whack-a-mole with ideas, meta-ideas and meta-meta-ideas etc. It requires serious PhD dissertation level study.