I also want to add a point to the discussion I don’t see on this page: how common certain tropes are. Sexy is the default for most female characters. Look at the females in SC2: Nova is also in skin tight armor with an ass-shot portrait. Kerrigan we have already discussed. The only other two I could find are Ariel and Izsha. They are less sexualized, though neither are playable and Izsha has non-mammal mammaries.
And this isn’t limited to SC2, this is common throught Blizzard’s franchises. Here is a list of all the women I could find for Warcraft III (feel free to skip).
Lady Vashj has more mammalian mammaries, along with the other naga: Serena, Serpentra, Scilla, Darkscale. And the sea witch, Zar’Jira.
All the elves wear sexy clothes, including Shandris in a bikini, Tyrande, and Sylvanas’s bare midriff.
This isn’t just an elf thing. The human mage, Jaina, also has a bare midriff. Even when they wear normal clothing, they must have well-defined cleavage! Just look at Maiev and Jennalla.
Many of the examples can be justified in some sense or another. Naga sexuality can be traced to their status as fertility symbols in Hindu mythology. But as yourself: why were nagas chosen? Why do we continue to focus on these symbols? “Because our ancestors did it” is not a good enough reason. Our ancestors had slaves and oppressed each other; they should not be the yard stick for modern ethics. The issue with these female characters is one of selection - every female is designed to be sexy. Their design can be justified, but somehow the world is filled with them!
In short, female sexuality isn’t just about narrative justification. This isn’t an in-universe problem. This is a problem with OUR society and US. Why are so many female characters designed to be sexy? Because it is expected.
As an example, consider a world in which everyone was an architect for some reason. It makes no sense. Why would everyone be an architect? Wouldn’t we get bored of architecture? Wouldn’t we complain about how kids are being taught that architecture is a common profession, when in reality less than 0.03% of people in this country work as architects? Wouldn’t every new character who is an architect be met with a roll of the eyes and a sigh?
Female sexuality is the same, but more widespread. In this context it makes sense that people don’t get as worked up about Raiden. There aren’t that many sexy male robot characters, but there are tons of sexy female robot characters. Raiden is less common.
And I would like to mention that I understand the push back. I like looking at sexy female characters (I am a man). But we are not advocating the complete removal of sexy females from everything. Just toning it down some. Making Kerrigan look more like the hive queen she is.