They did have more in mind for Sonya, but had to adapt things after the original actress (Cameron Diaz) got an accident and they had to replace her with Bridgette Wilson who had way less fighting training
I know that Jade was planned to be in as another fight or whatever, but because we don't really have any real grasp as to what capacity that existed in, I kept it off the table for myself.
The main thing for me was that Liu Kang and Sonya were essentially on the same journey. Both on revenge quests, with Raiden basically saying get over yourself. If there is a recurring element in the actual movie, it's about the control you take of your own life. Sub-Zero and Scorpion are literally said to have an absence of it - "slaves under my power." Johnny is the one who takes the stand to say "this is our fight," and Raiden takes a moment for himself to celebrate this.
So for Sonya, yeah, she takes down Kano, but she doesn't come away with any peace from it. Liu sees that, and kinda starts to question his own quest and how his grief and guilt are driving him to a fight he won't find quell his own pain. But Sonya? During that Goro fight, she sees a familiar face out of the corner of her eye - Kano still walking about. And without hesitation she goes after him, only for it to be Shang Tsung literally baiting her into a fight that she can't win.
The point was moreso to find threads within the movie, and see how to develop that into a more consistent and visible throughline without just writing a different thing entirely.
