We're currently working on a version of BGS that allows navigation of the background images via left/right arrows (JS effects only), like in a 'normal', i.e. foreground slideshow, or in a lightbox.
A bullet navigation could also be possible, however, the problem is where to position such a navigation - traditionally, it would be below the slider. But since this is a background slider, the 'normal' site content would hide it on scrolling.
On the other hand, if we position it on the left or right edge, what will happen on full width templates when a lot of images are set for the BGS...
We will however have a look at this, but i cannot promise that this feature will be added.