In my view, Diane can most definitely pull off crop tops and I think she pulls this one off just fine. I certainly wouldn't put the blame on her bustline, which is small as far as I'm concerned. The only nagging element that I dislike about this outfit are the white buttons. I would have preferred to see the full skirt maybe with a striped top (also cropped) or a crisp white shirt. Otherwise I think she looks great, certainly worlds better than the orangey, overly bronzed Lea Michelle.
But perhaps I'm alone on this as I see the consensus of late is that she's lost her touch stylewise.