It's true that a lot of effort is required to nurture a wiki, but many hands make light work, and I believe that the reward could be worth the effort.
If GovLoop just wants to be Social Network for Government then the blogs and forums more than service its needs, but if it wants to be more than that, if it wants to be a place that users visit everyday because it contains information that helps them do their job, then I think a wiki is the way to go.
I joined the "Subcouncil on Social Media wiki" a couple of weeks ago, and have had a good look at it. Its scope seems to be a lot narrower than the sort of wiki that I'm advocating. The sort of wiki I'd like to see would cover all aspects of government not just social media. It would contain a glossary of terms, links to resources, pages on activities like road building and sewer maintenance and water reticulation and much much more. It wouldn't be just for Web Designers and IT specialists, it would be for accountants and engineers and for all the professions associated with government.
I think starting a wiki from scratch would be the best option, as it would help the GovLoop community think of it as their project, but if you are worried about seeding it, I'd even consider cloning the LGAM Wiki, and handing it over for someone to modify and administer to get the ball rolling.
It has been frustrating for me that no-one else in the US or the UK or elsewhere seems to want to build the type of resource that I want to. It would have made building my project a lot easier if there was a similar project already in existence elsewhere, which is why I am agitating for GovLoop to build one, and willing to help out as best I can.