This is a very interesting photo - this would've been great for the Off-Screen Expectation (or whatever that challenge was called) awhile back. I really like the composition; the photo feels nicely balanced, and the colours seem to be right on. Clarity is excellent, and the title ties in nicely with the angle used. Focus is great here, too - nice work.
Without being able to even see their eyes, or better have them looking in the direction of the camera, there is nothing to draw the viewers into this shot. We are as closed off from the subjects as you were. If you have no interaction wtih them, neither do we.
Why do we not see their faces? And, if you choose to not show their faces, why not include what they're looking at so we have some added interest in the shot? As it stands this is a lack luster shot with no added interst to pull the viewer in. Add something that brings the viewer into the shot and connect with it.