Since the passenger wiper is out of the "critical visibility zone", deleting it might not endanger you too much. I have already seen many cars with passenger wiper delete in my home country, even though back here it's done more frequently due to lack of money to buy a replacement wiper blade than to any fuel-efficiency concern. But anyway, if I were going to make a single-blade wiper conversion, I'd most likely try to make it stand up while not in use like it's usually done in race vehicles to decrease the drag more effectively. Notice the wiper blade in this Brazilian stock-car, standing in the left side of the windscreen.
