My experience with modern contenteditable suggests that it does work pretty well, overall, though I've not been using it for something as layout-heavy as Docs -

My experience with modern contenteditable suggests that it does work pretty well, overall, though I've not been using it for something as layout-heavy as Docs -- I've worked on the VisualEditor for mediawiki, which has different requirements. A canvas-based document editor with any sort of international ambitions has a fairly high bar to clear for reimplementing basic features. The browsers really do handle a lot of useful things for you in contenteditable, like the upthread-mentioned RTL issues, and complex IME input methods. If you have a lot of HTML-rendering inherently required, strong internationalization requirements, and no need for something like page-based layout... contenteditable has advantages, particularly when comparing the up-front work required.