I must admit that if it were up to me no client would ever have a CMS at all. Even the Wordpress one, most clients with little knowledge of web development just make their own websites ugly whenever they add their own stuff. Or as you say break the site completely. They upload images at the incorrect size, resolution, aspect ratio, and quality most of the time. So I honestly do agree with you.
The problem is that some clients really want a CMS and no matter what I say to try convince them that it’s a bad idea that is what they still want. So in those rare cases it would be wonderfull to have something to give them, Advanced HTML Editor 3 was what I used to give, so medium editor with extended functionality would be great too.