Synchronistic! I also proposed some improvements to our search engine just yesterday. I see that our current system is working in some respects, but not in others. For example, I see that the search results are stacking up comments equally to posts, but that doesn't make sense because ~90% of the comments are not informative (the real information is in the articles usually). To me, comments are not equal to articles, even thought they are equally labeled "posts."
So, in addition to your proposal for improvements to the search functionality, please add the ability to exclude comments from the rankings, or at least priorities entire articles over simple comments. I support the idea of adding advanced filters, so we can organize search results based on timing, credibility (upvotes), and authority (reputation).