Google Docs does not make a good wiki.
- Optimized for printed page, not viewing online (page margins, document margins)
- Always in edit mode
- No mechanism to dynamically embed content or especially lists of documents in another document
- No friendly URLs for documents
- Does not link documents nearly as easy as in a wiki (requires interaction with menus/mouse and copying full URLs to documents)
- Does not support text zooming fully (appears to work, but try it, hit CTRL-+ and some document components often don't display properly. Basic documents work fine.)
- No cross-document consistent styling