Not many WS are 1.8 m tall - the Akane Y , Nozomi O, Tai Tzu Ying, He Bingjiao, Intanon R, Busanan O, Saina N, Zhang Beiwen, Cheung Ngan Yi, N Jindapol , Mitani Minatsu, all of them are shorter than 1.8m, I believe. Even Wang Yihan is 1,78m tall, Sung Ji Hyun, 1.75m, Sindhu, 1.79m. Among the top 10, the tallest, Sun Yu , is 1,83m about 6 ft. I'd say , for WS, 1,75 to 1.78m is good enough. Being too tall is not necessarily an advantage, more blind spots around your body, and, possibly, bending down low and recovering from that position may take a fraction of a second longer due to bigger weight.