Experience does influence how actors are paid. For eg., Pran saab was paid three times more than Amitabh Bachchan for Don even though he did not have a big role and Amitabh was playng a double role, was main lead and had also become superstar by then. Even Vinod Khanna was paid more than Amitabh for Hera Pheri because VK was senior to him in industry.
It is not always about gender. Neither is this issue about equality between Mahadev and Adishakti. Actors get paid for what they do and what they represent in terms of experience and stature.
Sonarika had every right to demand an increment in her salary but needed to be careful and reasonable in her demands since she is still new in the industry and had just completed a year in DKDM. Equal pay on par with other lead does not happen like this so soon (I am saying this on basis of rumours and arguments flowing here. I don't know if she actually demanded pay equal to MR's!).
Issue of gender is not the concern here.