Well Halep withdrew so I decided not to count her, it'd be like counting Serena for all those years she never bothered turning up to the YEC. I just chose the 8 who played and my points stands.I think you mean the players who played the tournament not the qualifiers because you are missing Halep who qualified but did not play and she will most likely qualify again (6th year in a row).
Pliskova, Kvitova, Halep and most likely Svitolina will make it again (expect Serena not to show up even if she qualifies).
It's pretty balanced this year - half older, established players and half young players who won 3/4 GSs.
Kerber and Wozniacki are winding down so no surprise here. Kerber is approaching 32 and Woz started a family plus health issues and now school (!?).
You can make excuses for players like going to school or just got married or **** like that but if they had truly given up then they'd retire. I'm sure Kerber and Wozniacki wish they were still qualifying and they'd definitely play the tournament but they're not, they're losing in the 3rd set of a 1R in Wuhan. Just a fact.