Interesting take on it. I have a different take. It looks like the two approaches could work together. My approach has an interesting quality in that it replaces the idea of truth with the idea of trust which is ultimately awarded by each individual. It let's each person describe their own truth through their personalized trust network. It looks like your block chain truth method would plug in directly as people choose to trust it and it enters their truth definition. Here is a micro-dissertation on it:
https://steemit.com/speakfreely/@dsonophorus/i-decide-what-is-or-isn-t-fake-news