I think traffic is one metric, and overall score of a link is another. Both are valid.
Traffic is fairly easy to measure, and ROI can be ascertained from that segment relatively quickly. It is link value that is more difficult to 'eyeball'
Personally, I am building my own tool for this which, will not take the work out of making final decisions, will be able to score links based on "assumptions" I have about link value (contextual, age of domain, number of inbound links on topic to that page, etc)