Ummm.... yes and no to the above posters. Yes, TouchWiz is just the UI layover, and yes, features like AirView and SmartStay are part of the system's features, not just the UI.
HOWEVER, some elements are still UI-specific, like some widgets and custom air actions (like moving widgets by moving your phone). Also, features like AirView are not accessible to all apps (currently, only stock Samsung apps and FlipBoard can use them), but installing a third party launcher won't affect how that works, for instance, in the stock browser (but you'll notice that Air gestures won't work at all on Chrome).