I own a 2007 Prius that I bought new. My biggest problem with the Prius is the blind spots created by the severe slope of the front windows. On more then one occasion I have come close to an accident because I did not see something that was hidden by the pillar. This is the 1st car I have had this severe of a problem. The 2010 does not look like it is any better.
I think you instinctively learn to lean forward for confirmation, just like relying on the side mirror primarily but turning your head to make sure... because that has been a complete non-issue for me. Scary thing for me is learning how many people only use the rear-view mirror for seeing what's behind them. Since they never had a hatchback, they were able to get away with not using the side mirrors routinely. The nice part about the slope is the window clearing. Stuff blows off in front really nice and the wiper in back is fantastic for snow compared to a sedan with nothing but warming elements. .
I agree, this is a known problem with this car. However, knowing this I am just more careful when I am in situations where it is important that I see from this view. I believe there are a number of trade offs we all have made in driving this environmentally friendly car.