A feedback scoring system would depend on the forum software; steveb0t, the wsc wrangler, would best be able to answer the technical aspects of that question.
Whether we want to have that or not, however, would be yet another decision/discussion/change. As I recall, we briefly had a "karma" system which totally backfired and caused way more isspay battles than we were prepared or wanted to deal with so we turned it of in fairly short order.
Lastly, a reminder: WSC is not a democracy, sorry. It is a community, yes, run by a few volunteers who mostly want things to go smoothly so they too can enjoy the camaraderie and shared enjoyment of a mutual interest with other like minded individuals.
This means that you can stop arguing and trying to convince each other about why your opinion on the need for stricter moderation in the Marketplace is needed or not. The louder and more belligerent you get will not make the moderators more likely to acquiesce. Nor will it carry any more weight with the members at large, because this is not a democracy and there will likely by no poll or vote. (I do not mean to say that we are not interested in your opinions, but that once you have stated them, you can relax!)
The admin/mod team have been discussing options concerning this issue off and on for some time now. Yes we've been slow about it, and there is a reason for this: WSC is not our day job. We have obligations, time commitments, families, pets, housework, laundry, and racing events - all competing for our time and attention. We'll get to it when we get to it, and more itchbaying and yelling at each other in this thread will only serve to get it locked as the previous one was. Please remember that we're all volunteers, and we'd much rather put our time towards positive contributions than have to spend hours dealing with arguments, complaints and drama llamas.