James Robertson has point out the obvious weakness of wiki tools: Wiki markup has no future:
The lack of WYSIWYG editing is a big barrier to adoption within organisations, and on the wider web. There are only a limited number of users that have the time, skills and inclination to learn wiki markup. It’s a fundamental usability problem, and the spread of wikis will always be niche as long as wiki markup remains.
This is a rather heretical point of view among wiki aficionados, however it is right on the money. If the outcome of using a wiki is to make content creation easy for a distributed group, wiki markup gets in the way of achieving that outcome. Most people can use a WYSIWYG editor if they have used a word processor in the past. This covers most Web users, especially in a corporate environment. Using obscure text code is an unnecessary and anachronistic hurdle to put wiki users through.