Presumably most, if not all of the main cast would either be soldiers or some similar role that grants them a backstory of combat prowess. Otherwise their inclusion would not make sense and would strain suspension of disbelief.
As for soldiers...rear echelon personnel are not held to different standards. A medic at some field hospital in the rear would not have long flowing hair blowing in the breeze, and looking like she has a staff to do her hair and makeup before going to work.
I'm all for characters being attractive if it is appropriate for that character, but their appearance should also match their role. A female soldier for example should have her hair tied up in a bun and she shouldn't be wearing a lot (if any) makeup. Now if you have a character who is the equivalent of Khalisah al Jilani and Emily Wong, thats a different story.
Excuse me, but this is grasping at straws. If you remove the makeup, the faces are still fairly nice looking. It's just a specific detail about Skyrim modding - a lot of customization can be done with textures and hairstyles(ie seemingly changing face shape without actual geometry change) and people use this to full extent.
Please take a look at the second person from the right:

Looks pretty, is a soldier, hair in a bun, no makeup.

Oh snap, another one. She even wears makeup, hory sheet, impossibru!

Well... You get the picture, hm?
There is a ton of other similar images of US, Israeli, Russian and Chinese good-looking military women on the internet. No reason not to feature good looking female characters in a sci-fi game.