If this hypothetical library is that good, then it probably meets your version of the general criteria I sketched. One problem is that it isn't always obvious w

If this hypothetical library is that good, then it probably meets your version of the general criteria I sketched. One problem is that it isn't always obvious what the quality is at the time you make the decision to take the dependency. I use size/complexity as a proxy for how much trouble it's likely to be.