I am a tenured professor in a division of epidemiology and biostatistics. My subject matter science included cardiovascular disease and sleep-disordered breathing, but my interest in recent years has shifted to research methodology, especially causal diagrams. As my CV shows, I have many "peer reviewed publications", extensive teaching experience, and even held an editorial position in a traditional "peer-reviewed journal".
What I think of the idea behind WebmedCentral:
I share most of your criticism of the traditional peer-review system in science. Personally, that system has caused me agony many times, especially when I tried to publish methodological articles that conflicted with mainstream viewpoints. Other times, my attempt to provide post-publication peer-review (in the form of a letter to the editor) has been suppressed. Several years ago, I even published a critique of the present model (Shahar E. On editorial practice and peer review. Journal of Evaluation in Clinical Practice 2007;13:699-701). Although I proposed a different solution, your model is better than mine in many respects. The only change I would have made is a technical one. I would have required a copy-editor to read the paper before it is published, to identify typographical errors and to offer (not impose!) changes that would improve the text. I am emphasizing the word "offer", because I never liked copy-editors who thought that their writing style was always better than mine.
You can find more about my views on my website (http://www.u.arizona.edu/~shahar/). Click on "exchanges on methodology" and you will find examples of the healthy debate in science that does not end with "the authors' reply". Scroll down the home page, and you find favorite quotes of mine that are pertinent to pre-publication peer review. One of these quotes fits your initiative very well. Maybe you would like to add it to your home page:
"If you restrict the journal to publishing only what pleases the referees, you end up publishing what is popular, and while it does make everyone feel more comfortable, you are guaranteed to miss the occasional breakthrough." -- A. Dessler