The problem with RWS is that you can't just point the front end where you want to go. Instead, you have to point the rear end away from where you want to go. While you might think the two are the same, they're not. It's a whole different paradigm.

As I pointed out earlier, FWD and FWS are not mutually exclusive. Personally, I like the concept of FWD. There are two styles of FWD, 'moving bottom bracket' such as the Cruzbike, and 'fixed bottom bracket' in which the chain twists as the front steering/drive wheel is turned. Although there are limits to the amount of twist the chain can handle, FBB is actually pretty efficient in normal use. The MBB style has the advantage of being somewhat no-hands-rideable, but the disadvantage is that pedal steer is tremendous, so pedaling hard causes control problems.