Heck, as a diamond mod I'm dissatisfied with the site at times too. I think we've shaken out a lot of our initial tone problems but still the content is pretty 4e-centric, or at least there's not a critical mass of content for most other systems, which does become a self fulfilling prophecy about people leaving because there's not enough here on whatever game they play to hold their attention. We've had to fight for more general, non-system-specific, questions to not be kneejerk vote-to-closed based on fear of subjectivity or whatnot, but could stand a lot more.
It's somewhat exacerbated by the small number of people in general that play any specific RPG, easily 1/100 of those that play any given new popular computer game, and by the fact that games are all commercially shepherded and publishers tend to have forums of their own for expert game support. The RPG community is fragmented and not driven by the hottest new release that provides some content coherence to e.g. gaming.SE. Unless you are one of the rare birds like myself that owns hundreds of RPGs, it's easy to feel drowned out.
There's the "scaring off newcomers" problem, but I think we've successfully convinced the community to be more welcoming and less "YOU DON'T KNOW THE COMPLICATED RULES HERE YOU ARE CLOSED GO AWAY." Some of that is inevitable because of the "SE way" but we can certainly be 100% friendlier about it, we've come a long way there but of course can always stand to improve.
I've tried to get people in my gaming group and from my blog to come here, but in general the responses I get are "seems fine, but there's what, one question a month on the game I'm playing?" It's not "It sucked I am leaving on purpose", it's "I have a limited amount of time so I'm going to go to the Paizo forums or Dragonfoot or whatnot - even though those are way less signal to noise, there's so much more traffic that there is still more raw signal there."
I think that largely the solution is to keep promoting the site, and to promote it to specific game communities, till we have enough quality traffic per game to keep people interested in that game.
I think that it's also important to make this site valuable in the Stack Exchange way. SE is successful because it is not a forum, bulletin board, or social networking site. I've seen a half dozen "social media site for gamers!" launch and sink within a month. The value of a Stack Exchange, and why it attracts experts and Google search rank, is that it is about people asking real questions they need help with, and getting specific answers. Not flame wars, not random noodling, not spouting off opinions. What we don't need to do in order to make this site appeal is deviate from the Stack Exchange formula - otherwise this is just one in a sea of sites, all alike.