I agree that the journal system provides a valuable filter. My beef is not with journal, but with locking up publicly funded research. Open-access journals are an unequivocal good.
But I am not convinced that all journals filter on the right things. I like the approach of PLoS ONE (http://www.plosone.org/), which assesses papers purely on the quality of the science, and ignores subjective notions of "impact" or "importance". The result is that everything they publish is good -- as reliable as articles published in any other journal -- but it includes articles that would never get into, say, Science or Nature due to the self-consciously super-selective approach those journals take.
Anyway, that's a side-issue. The real issue is that, whatever selection criteria a journal uses, it should make the resulting papers freely available to the citizens who funded them.