I’m using folders to organise my bookmarks. (BTW they are really quite nice already - keep up the good work!)
It would be nice if I could configure some of my bookmark folders so that I can navigate to the pages in them without having to expand the folder first.
I’m imagining the bookmark bar looking like
[Title 1] [Title 2]
[page A][page B] [Title 3][Title 4][page X][page Y][page Z]
In the menu when you right-click on a bookmark folder you could add an option below [“show bookmarks bar”] with the same 
toggle interface, perhaps called
[“Always show content”]
You could also put the option above or below [“Rename…”]