The lack of skillful storytelling aside, my biggest problem with these films was that both of them were so amateur in their technical approach. In Meeting David Wilson, you could tell that the filmmakers had access to decent cameras (and it sounded like they had decent sound equipment), but the quality of the image was still sorely lacking. Whoever shot it the documentary (obviously not David Wilson, since he was on camera throughout, almost, the entire documentary) seemed to have only a rudimentary idea of how to use a camera at all.
In 51 Birch Street, Doug Block (who claims to be a professional documentary maker), points what has to be some sort of Handycam at his family to build his doc. He shoots weddings for cash, and shows some clips of this in the documentary, but, if I saw those clips ahead of time, I don't think I would hire Block to film my wedding.
Unfortunately, this is the reality of the post DV revolution. We have many more documentaries being made than ever before, and because they're so easy to make, inevitably there are some that are suffering greatly from either lack of good storytelling, or lack of technical skills, or, worst of all - both.
It's hard when you can see great documentaries like I Am Trying To Break Your Heart, Hearts of Darkness, or, you know, pretty much anything that Werner Herzog has done. Don't get me wrong, shooting DV does not always denote a lack of technical skill. DiG!, which uses DV heavily, and Barbara Kopple's Shut Up and Sing, are both films that primarily use video to tell their story, and, yet, they do it in a technically proficient way. The people who are making these documentaries obviously know how to make them, whereas, with Wilson and Block and the like, these people seem to think that a semi-interesting story and access to a Handycam is a God-given mandate to shoot a documentary.
Though having to shoot (and sometimes edit) on film meant that many documentaries never got beyond the idea stages, it also meant that the documentaries that we did get were both technically proficient, and interesting (at least to someone). Films like 51 Birch Street, however, are really hard to comment on, because you wonder if anyone other than the family would be interested in the film. I mean, really, who doesn't know by some point in time in their lives that their parents are not the perfect image we had of them at some point in time?
Other films, like Overnight and Tarnation, have horrible technical quality, but have stories and characters so compelling that you can't look away from the screen. So, there is a flip side to the coin. You don't always need both sides, but, as in the examples already mentioned, you need to have at least one thing that's really strong (99% of the time it should be story, but you can't deny the value of something technically well made).