The fact that negative reviews require additional moderation and verification is not a problem, but if the review has sufficient detail and is negative, it should be approved without having to require the buyer to have submitted umpteen support tickets and have a face-off with the developer over the review content. Can you imagine if other products were that way? You buy a new appliance and have to have contacted LG support first before posting an honest review and then have to argue with someone at LG to justify why you wrote what you wrote?
My last review was extremely thorough and I had submitted 5 support tickets prior to writing it and it was still not approved and it wasn't even a bad review, it was 3-stars and pretty optimistic.
Negative reviews are critical to the purchase decision and push developers to fix their product quicker. It is misleading when I go to buy a plugin and all I see are the positive reviews because the negative ones were filtered out of my view so they could be "worked on" and made positive.
Frankly I am getting pretty tired of buying a new plugin and having to open several support tickets for broken things and then having to wait weeks on end for a response to my submission, only to have a dev (most of which lack any form of customer service skills) reply to me that it "works fine for them" and dismiss my issue as if I am a crazy person that just made it up. Sometimes a review is the only tool we have to combat this and you are taking that away from us.
You say this is the goal, but then you go on for multiple paragraphs about how if reviews mention broken things, they don't get posted. Or if reviews mention features that are missing, then they don't get posted.
This is the wrong perspective as well. The features that a plugin is missing should be pointed out as shortcomings, because often times people don't realize that they need that feature until they actually use the plugin on a live server. I don't think there is anything wrong with mentioning a reasonable feature/functionality that is lacking in the plugin that influences your opinion of the overall quality of the plugin.