How can you be so sure they're unbiased? I would worry a lot that this will just favor candidates who are more amiable and have less honest friends.
1) Gathering a larger number of perspectives
2) Asking gold-standard questions that get to the specifics and contextualized examples
3) Every referencer is tied to a specific work experience and provides their contact information, which helps hold referencers accountable to their feedback.
Does this not just mean trendy? Can you provide an example?
To give an example, recommendation might be due to "attended the same college" or "born in the same country". And this is probably not what you might be interested in.
If you build such model and control for these spurious referrals, you might be able to get better signal. (and hopefully also promote diversity of gender, nationality, age, etc)