Here are the things I would do:
1) Referrals contest: Prizes awarded to the people who recruit the most active members, not just a mindless numbers exercise. We don't need any more shitty people - we have plenty. Make the prizes decent, too: Cash, and some forum perk or another.
2) Change Advanced+ to applications. Monthly applications generate buzz, fun, activity. It doesn't have to be as stringent as Private used to be, just make it so that we know the nominees want Adv+, and that they're willing to put just a tiddly bit of effort into aquiring it. Probably a ppd and time requirement. Oh, and no exceptions.
3) Officially set the standards for Retired. It used to be that only very old, interesting members were nominated into Retired. That's no longer the case, since the Private merger - so make that clear and official. Retired aint that great no more.
4) Add an old member perk. No new areas or anything like that, I'm suggesting mod powers in their own threads. Incentive to create interesting content, and a fun perk for committed members. Disabled on abuse, or while carrying warn.
5) Moderators. Get rid of Elindoril and Boggart. Promote me, or Patrick, or Cody, or... actually, that's all I can think of. Then tell them what they need to do, and how to do it. Go over the rules with them, fix the rules where required. Oh, and make sure they all have identical powers. Oh (2), and stop contradicting each other in public. Concerns are raised in the Staff area - that's what it's for.
6) Administration. You're doing fine with the coding and development, clearly. We're the most advanced we've been in years on that front. But for the love of all things good and holy, promote someone to deal with the people? Promote someone with the autonomy to make decisions with people, when they need it, without farting around for months on end.
7) More announcements. Preferably about important stuff, like what's going on with the rules, the programs, the site-modifications. Maybe weekly updates on things like competitions, interesting debate threads, SotW winners, what's coming soon... Communication is king.
8) Knock out a 100 post day before the end of Summer. Or one weekend.
9) Stop free-for-all name changes. Jesus fuck, but that's annoying.
10) Remove rep.
Edit: I would also remove this Vigilink shit, and look very seriously at removing image ads too.
One last thing, please don't any bitchy moans about problems unless you have a constructive suggestion to offer alongside. Just don't.