I did not investigate the issue so cannot confirm this. I’d be careful with modifying core files as something unexpected may break down. However if you perform this on a staging/testing website and will not find any serious issues and/or javascript errors on your website that are somehow related to editing, then you may try it out.
Unfortunately replacing the default editor in WordPress is a PITA because it is not prepared to support other editors than the default one. The extension always had to “hack” WordPress to make CKEditor working, which is a bit sad.
The better solution for this issue would be to check what JavaScript errors are thrown and fix them. Perhaps an additional JavaScript method defined in editor.min.js has to be overwritten etc.
An ideal solution would be to convince WordPress to provide some sane level of abstraction to register alternative editors (just like e.g. Drupal 8 did). If this is available, finally extensions like this one could be widely used and seriously maintained.