The need for a multitude of voices
History makes it clear that diversity of opinion is essential. A guild of independent journals could take Wikipedia's vast collection of factual, but disorganized and badly written articles, "chop" them into smaller units and repackage them. Wikipedia cannot to this because they must never change their highly successful paradigm, with is one comprehensive article per topic, with as little POV as humanly possible.
Wikiversity and parallel efforts
I am not an expert in Wikiversity policy, but it is clear that we allow parallel pages and a bit more POV. A lot of people are trying to develop Wikiversity independently of Wikipedia. I applaud this effort, and it does seem to be slowly succeeding. But I see no reason why both growth mechanisms cannot coexist. Second Journal of Science is much better suited for hosting Wikiversity articles than Wikipedia articles, and for that reason, should serve to encourage quality efforts on Wikiversity.
Why a "guild"?
I will be interesting to see what happens when we get several journals, and inevitably displays questionable standards (such as failure to referee). It will then be necessary for Wikiversity to step in with something analogous to the {{Fringe}} template. The process will less painful if the journals have collected themselves to a quasi-self governing "guild", since the editors of these journals will possess more insights than most.