I've installed 3.4d (d3351) from the last nightly build (Jan 12) and it appears that the creation and editing of content is fixed in all but one area. If you try to create or edit content in the blog section of an out-of-the-box Quick Start site using the Web Editor, the buttons appear to be locked. The web editor functionality seems to work on the articles section though. You can create a blog article directly in the document library in Share to get around the issue.