Re: Next season predictions- slam wins, yec , tier ones or Pm etc
Since 2016, we have seen at least two new Slam winners per season (Kerber and Muguruza in 2016, Ostapenko and Stephens in 2017, Wozniacki, Halep and Osaka in 2018 and Barty and Andreescu in 2019). Given the current state of the tour, I don't see that trend chancing in 2020, which is why I think we will probably see at least one, possibly two new Slam winners next year as well. In my opinion, one of the two will be someone who has been at the top for a while, but hasn't managed to win a Slam like Svitolina or Pliskova (or Kvitova who hasn't won a Slam in a while, but is always capable of doing so) and the other will be a young player like Anisimova or Kenin or maybe even Sabalenka, who knows? The other two will be split between players who have already established themselves as Slam winners like Barty, Halep or Osaka.
I don't want to predict Premier Mandatory winners or the winner of YEC for obvious reasons and there are too many variables involved. The pool of players who can win majors altough considerable is still much slimmer than the one who can win Premier Mandatories.