Although WHR is not really about body shapes as we discuss about them on this forum, it is used with body fat percentage measuring. Miss A and Miss B have the same body fat percentage, but WHR reveals that A storages her fat below waist and B a bit more in her midsection. That's why they also call it the "Apple-Pear Index" here in Finland.
As Elisabeth noted, a lower WHR on women indicates general healthiness, higher fertility (or maturity) and easier childbirth(?). They have discovered a link between breast cancer and a high WHR.
But yeah, in style shoulders and height matter. You could calculate your waist-to-shoulder ratio just like WHR. For example, my WHR fluctuates between 0.72 to 0.73, and my WSR is 0.68 = Dem shoulderss.
If you need to minimize the effect of a generous backside, a curved upper back or big upper arms, use flat measurements from the front. My ratios in 2D are 0.73 and 0.70 at the height of 5'8" = soft rectangle with a tiny hint of hourglass.
If it's a nice day and I'm feeling good, then hourglass.
Don't know if this is any good, just a thought.
Edit:
I like measurements and ratios, because for me eyeballing doesn't always work. "Oh jeez, what am I?" is my most frequent thought when I look myself in the mirror, numbers make it a bit clearer.