I can visually see why the Wikipedia elite, might be disinclined to include formal mathematical proofs in general audience articles. They look intimidating.
It seems to me like the mathematics community on Wikipedia ought to be able to set up a new, top level Wiki-media project, along the lines of what Wikimedia Commons has become, dedicated to the sharing, presentation and interlinking of math proofs. The formal proofs could then be easily linked to from within Wikipedia, without making the Wikipedia articles harder for laypersons to understand.
Also such a top level project might be able to introduce some structure to proofs that would allow automated symbolic math processors to work directly with the public proof base. Also some enterprising Google geeks and/or college students ought to be able to bring some sophisticated search techniques along with the computing power of something like Amazon's Elastic Compute Cloud to the party. And that just might allow some truly amazing breakthroughs.