Like it or not, objectively speaking, Li Yongbo has to be the most successful even if you're reluctant to acknowledge he's the greatest Head Coach in badminton history. Indeed, just his very presence at the scene could in no small way galvanize his young cohort to perform up to his expectations - admittedly I was a bit surprised that he bother to turn up at the junior championships.
Golden ticket named Chen Qingchen? What about Huang Kaixiang, another doubles specialist and double gold winner here?
Akane Y has lots of potential, no doubt; she stands out among the best juniors in the world though not really head and shoulder above - Qin Jinjing gave her a good,close fight as I've pointed out and Busanan isn't far behind whilst at the adult/senior level she has yet to prove herself a top 8, let alone top 3, WS player as only time will tell (how else?).
This coming April's WJC will be very interesting and hotly contested, esp. in WS/GS as I expect Chen Yufei (who somehow performed under-par in the GS final earlier), He Bingjiao(who appeared leaner and fitter, a good sign), and again Qin Jinjing as well as Busanan and Aya Ohori (hopefully Liang Xiaoyu too) to be in contention for the GS title though Akane Y will still be the hot favourite. Among the Europeans, I'd be looking out for a certain Stoeva, iirc.