Ditto. And although I love and appreciate all attempts so far, all WYSIWYG type extension attempts so far have had quirks. There's some really cool extensions out there for Flarum that you get used to and if a WYSIWYG extension breaks or conflicts with just one of them, it's a real bummer. 😮💨
I've gone back and forth, but I am back to using the plain markdown editor.
I understand the periodic desire for WYSIWYG especially for forums where you have members who have never used Markdown and don't understand why when they accidentally typed
# hello it became huge text. 😆 Then I have to explain to them... so, the editor supports markdown, this is why that happened, blah blah blah. And/or, I'll have a user from time to time who just cannot understand the markdown link format.
Although I get the desire and empathize, the plain editor is much more lightweight and typically compatible with all/most other extensions out there for Flarum. I think Flarum would have had to START with a WYSIWYG editor... from the very beginning. That way as extensions were built they would be compatible and there'd be less quirks. But, that wasn't what the creators wanted at the time.
In short, be careful what you wish for (compatibility issues / slowness / quirks). And, there's the already mentioned rich text extension which is very close to WYSIWYG.