sry...I had experimental flag enabled, so I couldn't move bookmarks in Opera native bookmarks manager
that's why I recommended extension
Why can't you multi select your folders and move them?
box-selection (click with mouse in one corner and draw a box)
or selecting each folder with check box
You can also use "Custom New Tab Page" add-on to override New tab page with any URL, including your favorite add-on new tab page URL. I'm using it with my Group Speed Dial add-on and it works well.