The problem is, that she is depicted as caring mother. And such a person doesn't wear such a slutty outfit in public, but rather normal and decent clothes. Without her son it wouldn't be a problem, but with all the motherly behaviour it is misplaced, especially during the scene with Flemeth, when she says, that she will never be such a miserable mother like Flemeth.
A normal tunic with pants or something like Triss outfit in Witcher 2 would be appropriate in my oppinion.
Yes, because what clothes you wear determines your behavior as a mother. When I am walking down the street and see a woman with a child and she isn't wearing something "appropriate", the first thing I do is report her. She won't be raising a child on my watch! I also started a petition for all mothers to be required to wear victorian aged swimwear. Kids cannot be allowed to view their mother as a strong, independent thinking woman who is confidant and doesn't bend to social stigma. If you are a mom and you don't dress in full body clothing, then gtfo. Amirite?