On at least part of that I can definitely agree with you, PangTong. To compete against Kim and Asada must be like competing against people who have magical powers. It's like the problems faced by American ice dancers and pairs skaters in the days when Soviets had a virtual lock on the best training and most innovative programs in the world. When you think about it, even Asada must feel she's facing a buzz saw sometimes when she competes against the equally prodigiously gifted Kim. Can you imagine executing three double axels at the Olympics and not being good enough to win the gold? So times are definitely tough for ladies singles skaters. Great new for fans; truly grueling for skaters.
But a lot of the ways Nagasu and Flatt fall short aren't because their best is not good enough. (The 2010 Olympics being a glorious exception.) It's when they goof up that they slide out of competition. After all, Rochette pulled herself up to a medal, and she was not in contention at all during many recent years. It's certainly possible that at least Mirai could podium in such a field, if she skates what she's capable of.
As for Sonja Henie: when I read of her record, I was very excited to see her. But I found her skating disappointing to my post-Peggy Fleming eyes, as I'm sure you did. She had no extensions as she did spirals; she didn't hold any moves. Her back hunched as she moved. The lines that we value just weren't the style of the day. People hadn't figured out the potential of skating yet. Moreover, it truly was figure skating in those days: you won on the strength of your school figures. The person who began the change to more athletic skating was Henie herself, but she certainly couldn't have envisioned either the athletic likes of Dorothy Hamill or the graceful musicality of Janet Lynn.