It's my pet annoyance as well. Don't why they set the E46 correct way round and not the E39 nor the E60. I thought it was possibly due to the cost of any engineering changes not being made up by the number of units sold in rhd markets. With the E46, they were always going to ship more units so thats possibly why they did it on that.

Re the cam action, it still doesn't wipe as much as as properly arc'd wipers. Try it on a really dark, driving rain sort of night on country roads with little ambient light. with a dirty screen.

Even cars with single wipers miss settions at the top corners. Unless of course the windscreen was circular. Now theres an idea.