The problem OP is mentioning is exactly why I read HN and that I have a newsletter about the blogs of HN [1]. If you want to have opinions on a topic, the only thing you can do is read personal blog posts about the topic. I'm not sure you can make a search engine out of that, because at some point being the #1 will provide money to someone and he will be able to game the ranking. Look at Wikipedia on a business topic and you will see only the most popular tools are mentionned and on pinterest the results are now full of pinterest SEO experts. The person who will be able to prevent manipulation on the internet internet is going to be a Billionaire.
I'm very bullish on curation, especially at work, because employees should be less interested about their self interest and could curate the knowledge of the company, but for the web I don't really know how to do it