I have often thought that there should be a public ledger of some sort for people (powered by vouching), and then immediately forseen the negative externalities and abandoned that idea.

Reputation is as harmful as it is good. Anyone who survived being unpopular in high school, or seen the dummies that can be elected in democracies, should be able to explain how.

No, it is better to judge works by their merits than it is to judge people by their popularity. Though it is far more expensive.