I've said it before, but I think this move was a mistake. They've thrown away the benefits of a incredible wiki-based platform (where changes were pretty much instantaneous and any of us could easily make a difference to the docs!), the (actually pretty decent) WYSIWYG editor and an overall frictionless editing experience and replaced it with what, some (not even Markdown) document files in a GitHub repository. I honestly believe this will dissuade people from making small, quick fixes and ultimately drive away contributors.
When I last brought this up, I was told that there were a number of contributors put off by the wiki-based nature of the previous iteration and they will now be excited to be able to contribute using Git.
I'd honestly be interested to hear from any of these people. Given you could seamlessly login with your GitHub account, easily author your documentation and one-click preview your changes, what exactly are you gaining from having the editor gone and now requiring a local docs environment to do all of the preview/edit/commit steps manually?