WTA rankings are weird. how is Muguruza no 4 and Aga no 7?
I'm not sure I understand this question. I mean, yes, Aggie is a crafty player, and fun to watch, but she loses all the time, especially at majors. Garbine, on the other hand, won the FO last year, plus she tends to make deeper runs at the majors than Aggie. Given that, their current rankings make perfect sense to me.
That said, this could change soon. Garbine has been losing early a lot this year, and if she does the same at the French, she'll likely drop quite a bit in the rankings.
Of course, some of the same could be said about Aggie. She just doesn't make that many deep runs at tournaments, especially these days.
Sadly, the WTA is a complete mess at the moment. Even Kerber and Pliskova are having a hard time winning tournaments right now. That's why I'm excited about the comebacks of Sharapova and Azarenka. Both are far more capable of winning regularly and consistently than the current crop of contenders.