It just seems like the "which cars to scrap" problem turned inside out. We did that one and got nowhere.
viewtopic.php?f=1&t=32527

Now I am hearing some opinions to wikify this, on the notion that there are many experts and few vandals. I have my doubts, and clearly do others, notably the "1 in 8 contributors" datapoint we have above. There is an answer to that problem, in "reputation systems". Provide some primordial ability for contributors to rate each other's contributions, a-la ebay feedback, Digg, etc. Then number-crunch that to determine who is a good contributor and who is not. It takes some careful design (e.g. if the membership feels strongly about rating people for "rudeness", you better provide a "rudeness" knob or they'll turn the "accuracy" knob instead, to cataclysmic results.) But it can be done and can be done well. It would be a fun project.