Licensure rates are usually available on each individual program's website; I believe it's actually one of the data points that APA requires programs to list in their outcomes section. And rates of licensure for professional schools are by and large lower than for more traditional, university-based programs. Which seems counter-intuitive, given that you'd expect more purely academic (and thus possibly non-licensed) folks to have come from the university-based programs.
Again, I don't think the issue is really PhD vs. PsyD per se. However, the data indicates that the "worst offender" programs (e.g., those identifed by MCParent in his article) happen to offer the PsyD degree.
And even though grad school psych folks do, in general, tend to fall on the upper-end of the academic achievement spectrum when compared to the ubiquitous population at large, if all we're doing is comparing said grad school psych folks to one another, then we've essentially created a new distribution that should be fairly normal in its characteristics. Thus, the outcome metrics we've discussed retain their utility. It's not like we're comparing EPPP passing rates for clinical/counseling psych folks to the US population of undergraduate students or something.
RE: most people having to re-take the EPPP, I believe most people who take the exam (and most first-time test takers) actually pass it. The aggregate 2012 data from the ASPPB website, for example, indicates that >70% of folks passed.
As long as we're going with anecdotes, I personally don't know any practicing psychologists who've bemoaned their extensive research training. Sure, some wish they'd had more clinical training, but none felt unprepared to practice based on said clinical training, and not a one felt that their research experience was going unused.