It depends. If you throw it wide open, you'll get a mix. You also may not get some of the core leadership types -- many of whom are very busy between both fannish and non-fannish activities, because competent people tend to be in demand, and the kind of people who volunteer to do things get sucked into a lot of things. If you invite just the leadership, which demonstrates that it's more likely to be useful, you're more likely to get them.

For me, I'm not giving up a weekend of my time, or even a day, to listen to the kind of whining you describe above, or to discuss some of the topics you had on the schedule. I might do it to brainstorm and exchange ideas with other people who get things done, because that could be genuinely productive.

If the proposition behind this is "fandom is harmed by a lack of grassroots participation," though, I'll pass because I think that's a deeply flawed premise. Grassroots participation is all we have.