I cannot manage my favorite locations on the web even in the most simplistic way
This is not the case here, the Speed Dial can hold your favorites into folders. If that's not simple I don't know what it is?
The bookmarks bar too, it can have folders and sub-folders.
Also, they're developing a bookmarks manager in the latest Opera "beta/apha" releases (developer stream), take a look: http://blogs.opera.com/desktop
Duplicate topic anyway.