Focus area improvement
Focus area should be instead a focus point like this: http://jonom.github.io/jquery-focuspoint/demos/helper/index.html
A point is simpler to handle than an area for both editors and developers.
(but maybe I'm failing to imagine an use case where an area is useful)
Also, Fluid viewhelpers f:media and f:image return an attribute 'data-focus-area' that is not useful because the coordinates are based on the original image size and the resulting image has been, most of the time, resized.
It's better to use coordinates of a singular focus point X/Y that represent a percentage of shift from the top/left corner or, in alternative, from the center o the image (or the crop area).