I'm with you Stan....my old beetle had a flat side on wiper post and arm,
and never stripped a single time.  My GTI went through arms like there was
no tomorrow.  As far as I'm concerned, this is designed failure, pure and
simple.  And splines were gone on both wiper motor and wiper arm, so
cleanliness wasn't an issue.  Finally drilled a set screw into the wiper arm
and made a flat spot on the wiper motor to hold against.  Maybe that's your
upgrade.
Or you could put the wiper motor in from my dad's 1975 Dodge pickup--that
thing could tear loose a dogsled in Alaska, a la Buck in Call of the Wild.
A man's wiper motor.  :)
bmc  :)
"Faith will move mountains, but you'd better bring a shovel...."

 it appears that superior German
> engineering makes this the only vehicle that eats the wiper arms. Why is
> that?
>
> Stan