UK has a woman leader, Germany has one. These are top leaders in Europe and then, other nations have women leaders, Croatia for one. I'd have no problem with it.
As for the polls, it was on Voice of America. I don't think it was a "leftist article" as one poster may have inferred because in the opening paragraph, Harris and Warren and Clinton were mentioned. They have been involved in the talk of president for some time.
Nikki Haley or who else might be good on the GOP side? Marsha Blackburn, in the past, Sarah Palin. I think all of these are fair candidates. Nikki might be one of those one-off candidates, not because she's a woman but nobody really is like her out there.