I don't think it's valid to filter on resolution. For example, quite often a duplicate reported later gets more attention (useful discussion, votes, attachments) and so we resolve the original as DUPLICATE instead. GA has already commented on INVALID.

If you want more "qualitative" metrics you can look at the number of votes and comments (not saying that this is the right thing to do mind you, but it's similar to counting thanks and thumbs-up, ie it's measuring popularity). One thing that may be worth considering is giving extra points for patches.