Basic Wordpress is quite neat, but seriously dangerous in the hands of amateurs (i.e. 99% of Wordpress users). It's the insecure plugins that are the problem, as the article notes.
I had a couple of clients who were very keen to get their own Wordpress site up and running, and wanted hosting. My solution was to buy a separate reseller hosting package from 1&1 and ONLY use it for Wordpress. If any of the sites get hammered then hopefully they can't damage anything else. (and if they can get outside the boundaries of the reseller account that's 1&1's problem) Obviously I also warned the customers about unnecessary plug-ins!