Well, I pulled the trigger on the "upgrade" rear wiper kit for my 4066R. Has a new part number BXX10704, cost is $240 for the kit plus an hour install. Now I have a wiper that clears my line of sight when I turn around to back up. The new wiper cleans the glass up to the bottom of the right hinge and it extends (to the right) well past the hinge.
The original wiper started lifting off the curve in the glass right about where the reflection of the sun is in the second picture. By the time it got into my line of sight nearly half the wiper blade was off the glass. I even tried installing a longer blade as someone previously suggested, and bending the original arm somewhat - didn't help.
Should Deere have put a better solution on the tractor from the factory? - Hell yeah.
Am I happy with the result? - Hell yeah.
It was worth it to me, and snowblowing season will be here before we know it. That'll be the real test...