A while ago I listened to a podcast by Canon Explorer of Light, Rick Sammon. Rick's father was an accomplished photographer. He told a young Rick that if people are obsessing about grain in your images, then the images aren't interesting enough. Often the story told, or implied, by a photograph trumps absolute technical excellence.
PetaPixel recently had an article, "When Perfect isn't Perfect or: How I Learned to Stop Worrying and Love the Blur"
See it HERE.
This is mostly about blur, which is not so appropriate with portraits. But sometimes, gesture may even trump a little softness. And it certainly can overcome a little noise (I think).
I think of it as a sliding scale. As the quality of the gesture increases, the need for absolute technical excellence diminishes. And, vice versa. Do you agree?