A CMS usually needs to be accessible by many editorial contributors. More often than not, the people using it are not web and HTML savvy and the CMS is their gateway to creating web content easily. Because of this, a CMS is really a tool that must work like a well oiled machine. On top of that, besides working to actually produce your website, your CMS needs to work with your employees and their workflow.
It seems the ultimate CMS is one where articles and websites are created in it from the beginning with little to no use for outside tools. That includes not needing to use outside spell checkers, FTP programs, or word processing programs. I think this is the ideal that every CMS attempts to hit but I'm wondering how much everyone's staff or customers actually work in their CMS? Are the articles authored in word and then pasted in? Do they sometimes have to revert to using an FTP tool?
For us, we're pretty good at using our CMS but not as good as I'd like. My staff really prefers using Word and the commenting and highlighting features it has when authoring pieces. Once they have pieces to a certain level they "HTMLize" them importing them into the CMS. I feel this is a failure of our CMS because it's not being used throughout the entire workflow.
Could it be that creating content items in an offline wordprocessor gives people more of a sense of ownership and redundancy than composing directly into a text area in a publishing environment?
I have to to point to projects like the recently Google-purchased Writely.com. That service's success--as does the success of any similar offerings--will depend on how comfortable people are composing text into an online workspace.
Another consideration is the editorial process, i.e. the time from developing the content's concept to actually producing it. If that timeframe is longer than a single session at the computer you'd need to include some form of offline production.
Or at least have a cms with a stable versioning/drafting environment...
At least this way you know your HTML won't be full of <div class="mso_Normal"> junk -- just fairly-well structured HTML.