Typically, I'll limit clients to specific widgets and layouts and train them on how and when to use these elements for maximum effect. That's the only way to maintain design integrity. I don't let them pick fonts, font sizes, colors, etc. Authors are given a list of choices for the fonts, and these choices correspond to the font hierarchy specified early on, and they have to build pages within those bounds.
The idea is you want to give them just enough control to author the content they need (without weird hacks) and nothing more.