It's interesting you bring up academic journals - that level of academia operates on peer review! However, anonymity in the peer review process makes auditing and transparency difficult. The other thing about academia is that different disciplines have different standards for evidence. Each community of discourse establishes their own and I think there's value in those differences that a p2p system could express.
This is true. There are also means of assigning reviewers to papers, and other mechanisms that reduce the integrity of the peer review process.
Thanks!