CKEditor 4.3 promises to bring CKEditor Widgets.
CKEditor Widgets have been specifically developped for us (see http://dev.ckeditor.com/ticket/9764) and tailored to our specific needs, so we want to get them in immediately, possibly already with a 4.3 Release Candidate.
Back then in December, the proof of concept for Widgets was a requirement and a key argument to choose CKEditor over other alternatives, see #1260052-121: Candidate WYSIWYG editors ff.
Currently it doesn't look like CKEditor 4.3 would also bring us blacklisting support (see #2023629: Remove our CKEditor ACF work-around once ACF supports blacklisting.
But support for #1993928: Ability to set the lang attribute on specific elements for WCAG 2.0 compliance is still on the 4.3 Roadmap, see http://dev.ckeditor.com/ticket/7987.
Postponing this until CKEditor's 4.3 RC, though.
This blocks:
#2027181: Use a CKEditor Widget to create a stellar UX for captioning and aligning images
#1993928: Ability to set the lang attribute on specific elements for WCAG 2.0 compliance
See also:
#1858210: [meta] Content editing experience follow-ups — in-place editing and WYSIWYG
#2036253: Switch to CKEditor 4.2 upon availability
#1950098: Update CKEditor library to 4.1