I think the way forward from here is to emulate the systems used in scientific peer review and publishing. What makes Wikipedia work, in my opinion, is that is already emulates the model by which scientific knowledge has been able to accumulate: an "information commons" to which anyone can contribute and which anyone can use.
Until the 19th century, the scientific system was truly open to anyone, and credentials didn't matter much. As the quality and quantity of scientific information increased and its power to transform technology and society became evident, the stakes got higher and peer review entered the system as a way of trying to determine which scientific projects should be funded and considered reliable.
Right now Wikipedia is a hobby for most of the people who use it, which places it in a position analogous to the days when science was the hobby of gentleman tinkerers. I don't think many people right now are particularly using Wikipedia as part of their job or in any other context where they absolutely need to rely on its accuracy. When I personally look things up on Wikipedia, for example, I don't have to rely on its accuracy because there are other information sources that I can use to double-check anything I find here. If its reliability becomes more important to users, people will begin to develop more deliberate procedures for fact-checking and credentialing.
One way that Wikipedia could incorporate peer review would be to develop its own panels of accredited experts on various topics. Right now users are a largely undifferentiated mass. There are some differences between anonymous IP users, registered users and sysops, but those differences merely reflect different permission settings in the software and don't correspond to any distinctions in terms of individuals' actual expertise in specific fields.
In the future, we may want to have some volunteer committees: a science committee, a history committee, a humanities committee and so forth. These could be further differentiated over time as need be. For example, there could be science subcommittees in areas such as biochemistry or particle physics. Individuals with credentials and expertise in each field could be invited to serve. Suppose, for example, the science committee consisted of several Nobel laureates and other leading scientists. If a dispute arose over a particular article, the committee would be invited to mediate and render an opinion, and if mediation alone was insufficient to resolve the dispute, the committee could even be given authority to impose a binding decision.
All of these changes would consist of social self-organization of Wikipedia users. They wouldn't entail or require modifications of the software.