You can probably enlarge the quote to fill the width of the cover and if it's a quote from a critic, you might want to cite who said it underneath. That should take care of that area of empty space.
As for the dead space around the synopsis, the synopsis text is okay, but the line spacing is a bit too close together. If you spread it out a bit more, you can fill in that empty space below the synopsis and above the stills.
Then I think you might be done!!!

and thanks!!