I like your color approach and it would dfeinitely help to resolve some of the problems surrounding wikis. Unfortunately it doesn't help with the problem of updating/maintaining content. I think wikis needs a strong notion of ownership and in addition to that people, willing to contribute/update and maintain the stuff that they produce. If those requirements are not met it will end up being a pile of meaningless pages and links. I've been there myself. If I don't feel responsible for the stuff I produce, I'll never come back and update/maintain it.