Q&A services as discussion forums and evolving answers

Yesterday, I posted the following question on Yahoo! Answers "Did we have any real proof that man landed on the moon?"  In the past 24 hours, the question has solicited 10 responses and comments, provoking a compelling discussion on the subject.  Some observations: (a) two sides were clearly established (which impeded totally objective and thoughtful inquiry), (b) several responses express anger or resentment which take away from the value of the content, (c) the ratings of the answers don't seem objective - though these three qualities may be related to the political nature of the question - and (d) this level of discussion and debate makes my most provocative blog post look like child's play.  Also, when an answer is given "best answer" status, the question is locked to further updates.  This seems counter-intuitive.  At WikiAnswers - soon to relaunch (self-plug) - answers evolve and are perpetually open, as is the nature of a wiki.  This is both good and bad.  We also don't currently have a rating system.  Sometimes there is a satisfactory best answer and maybe the answer should be closed, sometimes not.  I'm curious to hear your opinions on this.  What's the most valuable approach for the user?