To me that is the problem with satin strappy dresses though. If it isn't tight and pulling, everything flops about under the satin, which catches the light to emphasise the "movement", or to hold things in place you get that pulling.
VB recently wore something similar to Brooklyn's wedding which I thought was quite well-designed to counter some of this, but still got plenty of nightdress comments. She actually had it quite loose over the tummy so you didn't get the light reverberating off your tummy "mound" like so many of them, and detracted from this with the detail down the sides.
I dunno, it's just whenever I see people in these dresses I think they had a vision in mind of how they hoped to look, and refused to recognise the reality. We wore them when I was in my mid-to-late teens (and Kate Moss was rocking the "petticoat dress") but we were all stick thin and wore them kind of loose and hanging. Although we all got away with it, I'm still not sure when I look back at it that we couldn't have looked much better in something else.