There's one reason why you don't want your windscreen to leave your helmet in totally dead air.
If turning and/or tilting your head doesn't help move the droplets, try waxing your faceshield (a little trick light plane pilots use up here in rain country on their plastic windshields). Rain-X might work too - if it's safe for plastic faceshields.
Some riding gloves have a built-in mini wiper blade on the left forefinger and you can also buy little wipers to slip over your finger if your gloves don't have the feature. The Green Light Trigger folks have their
Swipe product. I picked up a slightly smaller, but similar device at a local bike shop for $1.50, but the gloves I wear now have one built in, so I don't use it anymore.
If the gloves are soft and clean, you can just wipe with your hand, too.
To some extent, you're still likely to have to put up with some raindrops on your shield... they just haven't come up with a helmet (that anyone will wear) with a windshield wiper yet.