Yeah, I know. I first had it do nothing when you're not touching an object, but for the FPS view controller that doesn't make sense since it doesn't care about the distance.
I would say that if you are using the Orbit controller and click into empty space that setting the pivot point to a fixed distance of 1 meter is reasonable. Otherwise, we would need to change the ViewController API to include an extra flag 'setDistance' or so in lookAt.