The simplified markup provided is trivial. But you don't even have to supply that.

Again, the key feature of TWiki: you can edit any page, applies to everyone. Which means someone else can come along and edit your page. This might be a major refactoring, it might be correcting typos and adding markup.

The hard part (from the collective perspective) is getting information into the system in the first place. Once it's there, copywriting and editing tasks can be done by anyone. And once you've seen a few pages, you'll probably pick up most of the basic formatting rules.

I'm having this same discussion at work, where we're using TWiki to document policies, procedures, inventories, system configurations, etc. While the pushback I'm getting is "people won't learn the markup", simple truth is that paragraphs of text -- which I can't provide, because I don't know the background on a system -- are sufficient. Markup can come from elsewhere.

Example: I could have written this post in TWiki exactly as I've written it here -- five paragraphs of text. The only difference is that my <em> and <strong> tags would be replaced with _underbar_ and *asterisk* respectively -- and that only if I'd chosen TWiki syntax over HTML, as either is perfectly valid.