More in the way of looking at interaction between users, diversity of network, frequency, duration of formed links (especially this last one). Easier said than done… would probably be easier to apply in a commercial context.

Trust is a link maintained over time. There must be ways of looking at this that could provide meaningful insight.

(I got attracted by the concept of decentralized academic accreditation. It would mostly rely on multiple streams of human feedback, assessing the trustworthiness of the human giving the feedback is key and rather problematic)