I think Bollywood still has a long way to go, for making universal female-centric movies, for which we audience also have to show support. Female centric movies are very niche in nature, they are mostly dark, preachy and centred around a subject which is related to women's issues. Most of the female centric movies are actually social movies. They aren't made around a very fun or universal theme. Audience is habituated to believe that if a movie is female centric, it has to be about Women empowerment or feminism.
Now we all know that Hirani has only made movies on universal topics(other than Sanju which is yet to release). And being a mainstream director, he can't show a strong female character, unless it's a love story, and Hirani is not known for making love stories. When his first three movies,( Munna Bhai series and 3 Idiots) were released, female centric movies were not an IT thing. Actresses used to get shitty roles.
It also depends on characters, Munna Bhai and PK are roles, which were tailor made for Sanjay Dutt and Aamir. While in case of 3 Idiots, I can imagine Kangana pulling a female Rancho(I might get reported by TM for saying this). It could've created a balance between the three friends, by one being a girl. But as I said earlier, giving the strongest role to a female wouldn't have been an IT thing in 2009.
Raju Hirani takes years to make a movie, so it'll also take him some more years to give strong roles to females.
Btw, Anushka did have an important role in PK(the "whole" movie was from her POV), a movie which was mostly about Aamir unlike other Raju Hirani movies, in which even the supporting cast used to make an impact. Though it was kinda bland and forgettable role.
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