Purely from a tennis viewing perspective, I thought that the traditional post-US Open European indoor season which lasted until the end of the 00s, was a 'jewel in the crown' on the WTA tour.
There was so much great tennis and pretty well attended tournaments. Many players seemed to save their absolute best tennis for that time of the year and / or really come alive at those events, whether it was Hingis, Davenport, Henin, Clijsters, Myskina, Dokic, Vaidisova, Schnyder, Golovin etc.
A disproportionate number of the best matches of the year seemed to take place during those tournaments. I've always thought that a reasonably fast indoor court, was the absolute optimum setting for women's tennis, whether it was watching Evert vs. Goolagong in the big US indoor events in the 70s, Clijsters vs. Mauresmo in the European indoor events in the 00s etc.
However of course money talks. Especially as a result of the financial crisis, many of the European indoor event license holders and more crucially their sponsors decided to essentially stop funding women's tennis, and China / Chinese tournaments basically stepped in to fill the gap. Clearly the WTA to a far greater extent than the ATP in comparison, had to desperately seek to tap into the huge and lucrative Chinese market, to prevent a a noticeable reduction in tournaments throughout the year (and opportunities for as many players as possible to actually play at tour level and make a good living) or at least a sharp reduction in prize money (which clearly the players would have been deeply unhappy with).
I was unhappy at things such as Tokyo being downgraded in favour of Wuhan though.
The ATP did maintain a much better balance than the WTA of both tapping into the Chinese market while maintaining events in traditional markets, but the WTA had a much weaker hand in comparison and men's European indoor events were on a much safer footing than the women's equivalents.