A lack of active mining pools would be an indication that a coin is not being seriously mined in anyway. It's fairly easy to check pool stats. That combined with a missing developer and little to no trade volume would also indicate it's not being mined seriously. I think you have to look at the larger picture when determining a coin's health. PoB is still a new concept and it will take trial and error to get the selection process perfected. We certainly don't want to target coins in a hostile manner. Scam coins would certainly be a preferred target which would help rescue those left "holding the bag" as they say. Suggestions from the community on how to improve the process are welcome.