The real problem with Wikipedia is that it (the volunteer community) is not able to enforce even the core policies... And the foundation that owns Wikipedia only hinders the efforts of the community. I hope the world gets a better structured encyclopedia project one day.
EDIT: perhaps the worst thing about Wikipedia is the anarchic decision-making procedures, the so called RfC. It's supposed to be a discussion that results in a "consensus" decision. Except that the Wikipedia term "consensus" isn't what one would usually think of as a consensus, and it's not well defined. Somebody who didn't participate in the RfC discussion usually makes the call on what the consensus is ("closes" the RfC). Except that they don't even need to examine the discussion very much, whoever does it can basically invent the consensus.