Why wouldn't it be allowed to have a conversation about it? Maybe some players don't care about it. Maybe most don't. Doesn't mean it can't be talked about or criticized by the ones who do take issue with it. I wouldn't take anyone seriously who claims it ruined the game for them, but generally characters are a strength of the Witcher games and how a character looks and dresses is an aspect of them. For a soldier like Ves, who is engaging in guerrilla warfare, it makes no sense to be dressed the way she is unless she is completely suicidal. While her attack on the Nilfgaardians was reckless I didn't get the vibe that she wanted to die. She wished to protect the villagers who were about to be executed for aiding them earlier, and that took swift and bold action. That the game in the form of Roche points out how she is dressed doesn't help at all because it's a case of them wanting to have their cake and eat it too. It still makes no sense for her to jump to the villagers' defense when she's one sword to the breast removed from being seriously, if not lethally, injured. She is touted as one of Roche's best fighters, and yet this one female soldier needs to have her breasts on display.
Out of curiosity, what is the "lore" reason for someone like Keira being in permanent danger of flashing her nipples? I know magic made sorceresses beautiful but why do many of them love to show their cleavage? Does it stem from a sort of need to overcompensate now that they look they way they want to?
I agree that a conversation about it is fine. Looking through the comments section, though, most people don't want it to be a conversation but "proof that TW3 is sexist" or that people who like the game are sexist. A lot of commentators are accusing anyone of responding to the article's argument as "mansplaining" and "trying to speak on behalf of all women." Behavior like this really irks me if the discussion is trying to be civil and respectful. I think people who agree with the article could have made a stronger case by pointing out the silliness of some of the clothing like you have here instead of going on the offensive.
For the lore reasons, I won't be able to summarize the books well, but basically many/most sorceresses in TW universe were either orphans or rejected by their families as young girls because of physical defects. Yennifer used to be a hunchback. So as the women trained in magic they also learned to modify their appearances. Partly for personal vanity (not a negative thing) and partly to use as an asset. Most sorcerers and sorceresses in TW are politically active, so they use whatever assets they have to advance their politics. For the sorceresses, this includes using their appearance to influence men.
People have pointed out that it's sexist, but TW isn't making a case that this is positive (or negative) just that it's how the world works. So the games basing revealing clothing for sorceresses (not soldiers like Ves) can be seen to maintain this lore. In the specific case of Keira Metz, she is using her sexuality to manipulate Geralt, so it's actually very in character for her to wear revealing clothing. I haven't played the game for a while but I believe Geralt actually first meets her in TW3 when she's leaving a bath. She knows what she's doing by using her appearance as a tool.