As the driver of a customized Mustang with rear side window louvers and a rear window louver, I'm VERY familiar with blind spots. I've learned to use those big, shiny things mounted on the front of the doors. They're called MIRRORS.
As for the G5, it's an AWESOME car. I love the styling, the warranty is unbeatable, the as mileage is the highest of anything short of a hybrid sold in the U.S., and they ride a heck of a lot better than my bone-jarring Mustang!!
I agree about the blind spot. I rented a 2009 G-5 2-door recently, and felt really uncomfortable driving this thing in heavy Atlanta traffic. Look in the rear view mirror --- see nothing but the spoiler and perhaps the roof of the car behind you; look over your right shoulder --- see nothing but the sloping surface of the trunk through the small rear window; look over your left shoulder --- see nothing but the roof pillar.
It's all very well to make sarcastic comments about using the side mirrors, but the fact is, in heavy traffic surrounded by aggressive drivers, the mirrors do not give sufficient fields of view, and you can't supplement those views with your own eyes. That leaves you with nothing but just hoping that nobody is coming up behind you if you need to change lanes, and that they will be kind enough to not ram you.
Is this poor visibility common to all these small coupes? The Calibers that I've rented seemed to have better visibility, despite an even smaller rear window.