Let me just add my voice to the "I prefer the current separation between title and content" side of things.
For some of my notes, the title is identical to the first header; for most of them, it is not. In my mental model, the title is similar to a filename (and helps me find the note), but I do not need the title replicated as the first header of the note.
As this thread seems to be quite opinionated at times, let me proactively declare that I'm fully aware that other use-cases can differ and that I can fully understand that. But I'd like to keep my workflow nevertheless 
2 Likes
This sounds like a contradiction to me. Keep in mind that it will be superfluous if it is always kept in sync. Right now the note title is not the same as the first line of the note.
To me it seemed the reason why joplin used the first line to create a title the first time, is because setting the first line as a title is more helpful than "Untitled note" for example.
Compare it to a word document. Enter some text, save it. It will suggest using the first line as the file name, but you are free to change it. If you edit the document later, it will (obviously) not change the file name.
Some people might put a title at the top of every document that matches the file name. Maybe you’re one of those people. However, everyone’s workflow is different and many people (including myself) like to have a title (“file name”) separate from the note body.
5 Likes
Yes, I’m just imagining the nightmare of finding that all my notes have synced the first line to the title, removing all of the original titles and leaving them unintelligible to me.
Although I suppose that wouldn’t necessarily have to happen for the first line/title syncing to happen. As someone else mentioned, a toggle might be the best option.