I have just updated to 4.6.1 and I lost my standard visual editor as well. The content appears in the Text tab but the Visual tab pane is blank – I deactivated and then reactivated all my plugins and NGG Gallery and YOAST SEO were causing the problem. I installed an old version of NGG and that is working and I tried using an old version of YOAST but still no luck so I have to leave it deactivated..I activated TwentySixteen theme to make sure it was not a theme issue.. Would like to reactivate YOAST if you can sort this problem out
Interestingly if I click from the Text tab to the Visual tab the content appears but if I edit the content and update the page the content stays as it was – if I edit in the Text pane then it stays after Updating the page
The Black Studio TinyMCE Widget Visual editor is working OK when YOAST plugin is activated