Klingon does have quite a big amount of written stuff already.
However, wikipedia is an enciclopedia, so the question is not whether the language can be written, but whether people would actually write enough *encyclopedic content*.
A possibility would be to require showing some real activity, eg requiring having some 200 or 400 articles before fully accepting a conlang.
And where would they write all that? And why don’t we pose such a criterium against all those tiny languages too (not being anti-languages, here, I hope you see my sarcasm)
I don't see anything "embarassing" with klingon; but the fact is people that use klingon do it for fun, not to communicate knowledge, much less to build a repository of human knowledge like an encyclopedia.
But some of them want to, that’s exactly why they are or have been asking for a wikispace here. (duh!)
PS: it seems the mail server is crapping itself yet again and is sending out months old stuff now.