I don't think you can create a for-profit business that is trustworthy here because the incentives are too messed up. You could do an open non-profit structure

I don't think you can create a for-profit business that is trustworthy here because the incentives are too messed up. You could do an open non-profit structure where all reviews can be analyzed, including "removed" reviews (have a second data feed that is raw, with the appropriate disclaimers").