I think the the women average 5'7 to 5'8, with a fairly normal distribution with as many outliers below 5'4 are there are above 6'0. I don't think power is directly correlated with height in women as it is with men, Serena is a great example. While being taller helps, you are not going to see 6'-9 women who will change the dynamic of the women's game the way a Del Potro or Isner or Querry can do it in the men's game. Unfortunately, I think taller women in tennis is going to the norm going forward, but I think this will be more a function of selection bias in allocation of training resources, i.e, a self-fulfilling prophecy, rather than the result of true competition. Too many experts eying the size of the parents, coming up with a "projected height", and then letting that bias there decisions, rather than results.