Alternatively; a two value system measuring popularity of the sentiment expressed and separately the quality of the post. So for example, a poorly written post with good ideas would be: legibility: -4, popularity: +4. This could be expressed as an rounded average or different users could filter by their own preference of legibility/popularity.

Of course this would all be a fairly major change to a system that isn't really broken so it's just speculative thinking on my part.