DraftJS is good and is one of the best React frameworks to create rich text editors. We removed it because it didn't fit our product.
After running multiple tests, we realised developers in the community were happy using plain <textarea> with basic markdown support than WYSIWYG editors. Also, we wanted to keep things simple and straightforward in this new Hashnode.
If we have enough time, we might open source the DraftJS editor that we built.