Nice proposal for living documents, but how do you suggest measuring importance? Journals are a low bar -- it's too easy to publish crap and yet many of the most important papers were rejected by the prestigious journals they were first submitted to. In my opinion, decoupling dissemination (what arXiv provides) from endorsement is desirable. Endorsements should be revokable and non-exclusive.
I think you're mistaken about the quality of journals. They work most of the time, although the anomalies you mention do occur. If it was so easy to publish crap on journals as you suggest, these same journals would not be so prestigious and used as an evaluation tool by university departments worldwide.
