I think the QA section should serve that purpose. Say that you got something bad and has negative review to tell. First of all, you have to eliminate your subjectivity (whether it is just you and your one specific product out of the lot, or is it everyone and everything out of the lot). Only the vendor can help you here first, and not the whole world. If the vendor is bad, then it is the platform’s fault (they didn’t help themselves by helping host the vendor). The best you can do is ask a ‘why’ question (why it is broken, or why it is not as advertised). Enough people asking the same, would naturally help everyone.

Now say you got something good. Again, you have to first eliminate your subjectivity. Why should the world care if you like something? But you want to help others make a good decision. Fine. Let them ask questions genuinely and then you can answer. Platform should let that happen because otherwise vendor would never let others answer on their behalf. QA should be the only place for interaction. Question should only be posed by potential customers. Answers, only by known customers.

Crowd sourced reviews are first and foremost subjective. They spawn either a fan boy syndrome or ‘I’m going to get’ you syndrome. If not either of them then they have spawned a whole new underground market of their own. Indeed, they have not proven to naturally balance the real and legitimate market; otherwise, they wouldn’t have been gamed. But Amazon does have QA alongside reviews. This makes it obvious that reviews are their cash cows using/abusing human psychology - of greed and gratification.