Most important "business" lesson I ever learned: never write a "document" in an email message; write it in Word and attach it instead, to activate the pointy-haired neurotransmitters.
Don't even try to make the conversion full featured, just rip it plain text. When the boss asks why his charts and headers don't convert over, show him how easy it is to fix that in the wiki. By getting his feet wet this way, eventually he might not even bother uploading word docs at all.
Or maybe I have too much faith in pointy-haired bosses.
The rational response to that from the PHB's point of view is to ban wikis.
This is precisely why both of my last two employers actively forbade real Wikis in favor of dumbed-down Word document repositories.
PDFs are a really valuable tool when you don't want people to modify your document, and you have the political capital to refuse changes.