I've seen similar dresses on women and I wouldn't call them frumpy at all. The colour is beautiful, and these dresses have always looked really elegant on whoever I have seen it on.
I really don't know where all these non frumpy/ stylish fashionistas are because when I am out and about most people are dressed like they've just rolled out of bed. In fact, the best dressed, most well groomed person I know, was wearing a version of this from Baukjen a few weeks ago, in this colour, and looked stunning.