You used to see plenty of complaints that the monowiper couldn't keep up in heavy rain - it didn't clear the windshield nearly as well as a conventional setup. Also, the monowiper does not do as good a job of clearing the windshield in front of the driver - it leaves the upper corner unswept. But it does a better job clearing way over on the passenger side. I don't think this is a good tradeoff. So maybe it was a customer satisfaction issue? Possibly even regulatory in some markets?

Or maybe the stylists dictated that it go away. The monowiper didn't hide when parked, unlike conventional wipers. For that matter, maybe the aerodynamics are so finely tuned that hidden wipers are now a necessity.

I liked the monowiper - but mostly because it was unique, not because it seemed to work any better. As I've postulated before, I think it was mostly a cost cutting measure by Benz. The monowiper permits the same setup to be used on both LHD and RHD cars - just set which side the blade parks on. A conventional setup is completely different between LHD and RHD cars - more different parts, more expense.