To be fair Google Docs is a bit different here. To a large extent their goal is to display what is going to be printed (this is changing a bit with the new page

To be fair Google Docs is a bit different here. To a large extent their goal is to display what is going to be printed (this is changing a bit with the new pageless mode and things like checkboxes but still is the core). So doing all of the rendering themselves actually makes sense. That being said I would love to see a rich-text input with some default controls available.