WYSIWYG editors (Word, OpenOffice) generally don't see a reason why anybody else should mess with their files, so finding an editor which a non-technical user can use and which is friendly to a version control system is impossible. Exception: git has a filter which can look into OpenOffice files. I'm not sure if you can use keyword expansion, though.
I suggest to use a wiki and a week of training for your users how to use it. It solves all your problems (some wikis can even be checked into a version control system). As I said in a different post, the sole obstacle is that users will take a few days to get accustomed to the idea. After that, they will love it.
