One of the signature Wiki features is that people edit pages over the web, often anyone and without restrictions (as the original Wiki was/is). It's said that this is a defining trait of Wikis, and that without it what you have isn't really a wiki.
DWiki has no from-web editing of pages. There are several reasons why.
A web browser's form input text boxes are a totally crappy editing environment compared to what I have on a Unix system. Yeah, sure, I could require Javascript and load a huge editing library and maybe get somewhere, but a) I browse with Javascript off and b) am I going to get half as good as GNU Emacs or vi or sam? (I don't think so.)
So I want the primary way of editing DWiki pages to be from Unix, through the filesystem, with real editors. (And it is.)
The principles of global edit permissions leading to the world help write your pages simply don't make sense for us. DWiki's goal is to let us easily document how our Unix systems work. We're the only people who can write most of that documentation; outsiders can at best add side commentary.
This would be different if we were interested in running a Wiki on system administration best practices or the like. But we're not; we're just documenting our systems. We let other people read it so that they can learn from anything interesting we do (and that's primarily aimed at other people at the University of Toronto).
Anything that allows semi-public writing on the Internet requires tending. Wikis are no exception to this rule.
Like many places, we are historically very bad at creating documentation. The more effortless I can make the process, the better the odds that we will actually write documentation.
Keeping DWiki running is part of the overall process; the less effort this takes, the better, especially if we aren't actively writing documentation at the time. Thus, I don't want DWiki to take up any time when we're not actively writing things with it.
If DWiki allowed web writing from anything except a small set of people, we would have to tend it. It is simpler and less risky to avoid that, especially given that we can't expect significant contributions from outsiders.
Eliminating web-based editing immediately kills the need to tackle a bunch of hard problems, because Unix handles them for me. Particularly, I don't need to authenticate people or do access control, provided I'm willing to let everyone read (I am, so far).
Access control, authentication, and registering people is not an easy area. It's also one where failures and program bugs can have severe consequences. Not having to worry about that means that DWiki is faster to write, smaller, and safer.
I also don't have to worry about random outsiders writing pages that make extensive use of expensive DWiki features, or writing things in pages that cause rendering errors.
Pragmatically, the odds of us wanting to edit our systems
documentation from anywhere that we can't just run ssh to log in to
our servers is fairly low. This is especially the case given that
there are Java SSH applets, so that any browser that runs Java can let
us log in to our servers.
DWiki is aimed at the low-hanging fruit of the 90% or 80% or so solution. (I maintain that any wiki is, partly because the text rendering is deliberately simplified.)
The most likely web editing feature for DWiki to pick up is to let web people write comments on pages but not edit the pages themselves. This would let outsiders give us feedback and commentary without running the risks of scribbling over valuable page content.
This would still require me to either write an authentication system or live with the likelyhood of comment spammers showing up to yammer madly. Plus some of the above worries.
(The clever person will notice that some of this future has arrived. DWiki now has an authentication system and comments, although both will be improved in the future.)