As a one-handed backhander i find this a very interesting discussion.
If we look at empirical evidence, is the one-handed backhand really worse?
5 of the current top 20 in the world have them (Federer, Gasquet, Almagro, Warwinka, Kohlschreiber; 6 if you make it the top 21 and include Haas); they are successful on a variety of surfaces and with different overall styles of play. I don't know if 25% of the players in their generation(s) were trained on that stroke.
Anyway, I'm just glad that people are even discussing the one-hander and hopefully there will be a better understanding of the stroke and how to use and teach it properly. We can use all the resources we can get!
Disclaimer: I'm NOT a coach...
Real tennis: https://www.youtube.com/watch?v=yDqnkLJ9BtM