Hmmm. I think I'm like Cinnamon Fern. I really really want to like the dress and I think that Deborah's suggestion of a waist defining belt is a really good one, but... I'm not sure this dress is worthy of you. I think your body shape is a lot like mine, so I think I have a reaction to this based on my feelings and experiences with this shape of dress. I don't have a super defined waist. I love the look of fit and flare or skim and flare (as in skim your body and flare on the bottom) on others. When I put them on, as heartbreaking as it is for me to admit it, they're never a true winner. I might even buy them, but after the initial crush is over, they languish in my closet. Ultimately, both my eye and my brain know that a basic sheath or a sack dress shape work so much better for me. The first defines a waist for me and the second makes you imagine a waist. So, I think this looks okay, but I think there are dresses out there that are more deserving of a home in your closet.
ETA: I just went back and saw you in this NAS dress. Holy wow! You + that dress = FAN-TAS-TIC! Perfectly illustrates the point. This dress? Okay. That dress? Oh yeah, it totally gets you. You are smokin' in that one, babe!