Most authors do not want another browser editor. Microsoft Word already handles drafting, comments and familiar editorial exchange. The publishing layer should accept that manuscript and do the web-specific work.
Import with an explanation
Word heading levels become chapters and sections. Captions, footnotes and links are recognised. The author receives a report of anything that could not be converted cleanly.
A revision is not an overwrite
Uploading a new manuscript creates a private revision. The author sees which sections were added, changed, moved or removed while the existing public edition remains untouched.
Preview before publish
A private preview reproduces the phone, tablet and desktop reading experience. Only an approved revision becomes public, and the previous edition remains recoverable.