This isn't particularly deep analysis, more just aggregation. Here's my take on the results, though, after some totally biased and ad-hoc tallying:

A total of seventy-five users responded. Convenience, scheduling conflicts, and other personal issues were by far the most common reasons not to attend, as a factor in almost half of the responses. Unfortunately there's not much we can do about this, except possibly giving more thought to location when scheduling, and that seems unlikely to happen given the issues I've seen with finding space and time. Two people felt uncomfortable with an otherwise convenient meetup's location, with a third having no personal complaints but describing complaints from others.

After that, a perception of the participants as too nerdy, weird, or socially awkward seems to be the most common complaint, with ten people citing one or more. A couple of these respondents attended no meetups and were presumably working from perceptions of the LW community at large, but most had. This seems to be a pivotal issue with our community's perception, but I'm not sure what to do about it. I imagine many feel it's a feature rather than a bug.

A lack of structure is a close third, at nine responses. Often this involved uncertainty over time and location, or scheduling difficulties thanks to inadequate information. Games and unstructured discussion seem to be seen as adding little value, with the latter in particular cited as allowing unproductive debate between a couple of participants to dominate meetups. Bad discussion norms were specifically mentioned as a factor in four responses. These are probably the most serious issues we can immediately do anything about: I've personally participated in both structured and unstructured meetups, and the difference is night and day. Establishing some best practices here would go a very long way.

Seven people felt that their meetups were unproductive, adding little value in terms of practical rationality or other useful skills; six complained of boredom. This is likely related to the complaints about structure; several people mentioned both.

Another six people felt intimidated by meetup participants or the LW community, most citing perceived intelligence or technical knowledge. Conversely, five felt that meetup participants were generally unimpressive (my notes say "not awesome enough"); most of these describe a hope for more accomplished peers, perhaps along the lines of Eliezer's mandatory secret identities. I suspect this might be an oblique way of saying they're too nerdy, as above.

Two complained of political differences, and two felt their meetup wasn't diverse enough.

Finally, two respondents described harassing behavior from a participant or organizer.