In reply to Spark Development.

Actually, you could add weighting for different release types (major/minor/maintenance) but who's to say that a maintenance release isn't more important (from a security point of view) than a major release, as they are often released to target a specific issue, whereas major releases address multiple issues and add functionality.

Another thought - these individual scores could be shown against each plugin/theme on the updates/plugins page. Could even add some colour-coding?

This is all assuming that the out-of-date plugins are on sites managed by people less-interested in the technical detail and more interested in actually running their site to achieve sales, publish content, etc.