Glass is affected by all sorts of pollutants. Insects particularly have waxy bodies and this makes wipers jump and skitter as they sweep across the glass. I would try cleaning both the glass and your wiper blades with bug & Tar remover which is a citrus based cleaner. Shouldn't damage the rubber at all.
Regarding condensation on the outside of the glass, this is an effect of moist air outside coming into contact with very cold glass, it's a law of nature that condensation will occur, not a fault of the vehicle. If you must use the air cond at this time, you should apply some heat as well so the air inside the car is dried by the aircond, but warmed by the heater, so the glass doesnt get too cold.