The point I disagree with the most is that users won't need training to use it. I hear this all the time with absolutely nothing to back it up, other than "I haven't trained a user to use it".
Well, I have, and the users for this company struggled a lot with how things will work. I've trained users on numerous scripts, including Umbraco, Sitecore, Concrete5 and bespoke CMS's and every one of the others were far easier to both sell to a client and train. Umbraco and Concrete5 are far better for users than WordPress.