Victoria is hot like the Venus fuckdolls, objectively yes but not based on anything that really matters (like not being a corporate drone/sexbot for your former asshole boss). Any scene with her in it is an automatic pass for me.
Background =/= personality.
Chandra is fierce, cares for her friends, tries to help milchers, and rebels against her mother as much as possible.
Katie is empathetic, tries to help out the unfortunate, cares for her friends (including the MC), and is sweetly shy.
What do we know about Victoria's personality? She's cold, manipulative, will do whatever Meredith wants, is loyal to the company, and only towards the end starts to doubt the rightness of what the corporation is doing.
Part of Victoria's charm is the difficulty in knowing where her corporate facade ends and her actual personality begins. Is she sincere when she apologizes for breaking into the MC's apartment? What about when she appreciates him calling her a person and not a tool? Maybe when she says he fascinates her? Surely she means it when she says she doesn't want him to die?
Who knows. You could make a case for or against any of them.
The other thing to note about Victoria is that she has a lot more to lose than the other girls. Katie is a street doc who already lost her shot at a real license. Ellen is a washed-up has been. Chandra is a rich girl used to dealing with first world problems. Gloria is going to be hunted no matter what she does. None of that makes them weak characters, but it does mean they can wear their heart on their sleeves pretty safely.
By contrast Victoria's position gives her considerable power and influence, but also has a lot of strings attached - namely she is a professional manipulator and someone else always calls the shots. So unlike the others, Victoria needs to keep her thoughts to herself most of the time.
That doesn't mean she doesn't have those thoughts; it's pretty clear she does. We just can't be sure which thoughts are really hers.
Looking over the whole of Victoria's possible interactions, I'd say she's introverted, has a very droll sense of humor, and has a deep disdain for her work despite also taking pride in a job well done. I'd call that a personality, but YMMV.