One nice thing is that (in my opinion) it can reasonably be done incrementally rather than having to release it all at once. Obviously I don’t know if that’ll be the case from a technical perspective, but from a user perspective I think it would be fine. Some logical separations might be:
- Pasting text that becomes formatted, including things like bold, images, and links
- Autocompleting mentions, categories/tags, emoji
- Keyboard shortcuts like Ctrl+B for bold
- Toolbar actions, like bold, hide details, blur spoilers, etc.
I feel like each of those groups could be done individually without confusing users, and personally that’s the order I’d implement it in.