It'd be interesting if there was some way to measure user satisfaction per release. It would be nice to know which versions are working well for people and which ones are breaking things.
Identifying user satisfaction automatically is more tricky (sentiment analysis, which would be amazing, but we don't have the resources to do that well).
For now, one of the things we might do is to ask people to specify a version whenever they rate/review a package (or somehow deduce that automatically based on the date of review, which would not be as accurate...)