I sit a bit over an arm's length away, and I've got gorilla arms. I find that to be totally comfortable with this thing for desktop use.The 57" 32:9 screen's height vs. curvature amount makes it so that it's not realistic to sit at it's center of curvature, but there is probably a sweet spot where the screen height still looks decent to your perspective and the effects I talked about are at least minimized compared to sitting closer than that sweet spot.
I think it's a good sweet spot where it doesn't feel too tall, or too short. I don't feel there's any benefit to it being any taller or wider. Sharper? Sure, but it'd be tough running say a 10240x2880 (dual 5K) or 12288x3456 (dual 6K).