No, I like them in that concept art.
I also like them in this concept art:
I like the ones on the right side, too. Their face is similar to the typical viera facial structure. They have an air of mystery about them like many woodland creatures of folklore, and also a certain elegance to them. To me, viera fit a fantasy, magical, woodland creature trope. I think a hulking, brutish looking viera doesn't really fit the theme.
They are not as buff as the picture Theodore posted shows. They look lean and fit in the concept art, and I think it's perfect. Elegant isn't a buzzword, and considering your character model choice, I'm sure you have your own bias, as do I.