Yes, that's your main problem in a small wiki. You also have to get people use to that idiotic wiki-markup (WHEN will we have a NORMAL WYSIWYG?????) and they are good scratch-boxes.
The problem with WYSIWYG is that it goes against the concept of separating content and presentation. There are lots of different ways of displaying the same wikitext (see all the different skins, but that's only the beginning of what is theoretically possible), WYSIWYG encourages people to write stuff that only looks right in the skin that's used on the edit page. Writing in code encourages people to just write the content and let the skin worry about the presentation, which is generally preferable.