A sexy/sexualised character design doesn't mean the character is "presenting him/herself" as sexually available all the time. Unless you suppose that certain attires are a sexual call, but I find that a very bad territory to enter.
Even so, keep in mind character designs don't change in game, they're usually static. The comparison between humans and characters with regard to how they act/present themselves differently in different situations , especially if we focus on appearance/clothe-design and not behaviour, is moot. Also, sex appeal and "trophyfication" are two different things.
Unless you remember it's a game, so everything is a trophy, in the sense that it's here to please the player.
The "aimed at boys" is very sex-essentialistic and wrong, unless you don't think what can be sexy to boys can't also be sexy to girls. And there's nothing wrong with titillation as entertainment, it can be quite entertaining. Also, a design that might appear overly sexualised to you, can simply be over-the-top/cool/fun to someone else. That's perfectly ok, you're not obligated to like anything you don't want to, but what you can/can't find relatable/non-jarring is merely an indication of your tastes, not that there's something questionable in the content.
The point for that is, that both sexy and sexualised are subjective. What I consider sexy you could find sexualised and vice versa. I personally find, some people use sexualised as a term to "attack" something that they don't like and has sex appeal. I haven't found a convincing difference between sexy and sexualised so far.
It's a vast topic, we can expand, but I feel we'll ultimately end up disagreeing.
I think where a character and a person differ in terms of sexual presentation is that a person has agency over what they are doing and a character doesn't. If s/he is being presented in a sexual way, there is a person or persons deliberately designing them that way behind the scenes. With a real person, they can choose to sort of turn their sexuality on or off, to so speak, in the sense of whether they are trying to behave sexually at any given time. The lines are much less clear with a character whose every word and motion is by definition not their own. I wouldn't say it's a moot comparison, but I think all of that is worth bearing in mind.
I do not say 'aimed at boys' to be gender essentialist. I fully expect that some women also enjoy such depictions. In general, however, sexualised depictions of women are not aimed at lesbians or bisexual women, they are aimed at men, and the people utilising them will freely acknowledge this. As I understand it, what 'reads' as sexy and appealing to lesbian women is not always the same as what reads as sexy and appealing to men (for example, you will sometimes see lingerie ads or the like with two women in bed together, but I have read articles about how this kind of 'performative lesbianism' is not really what interests or appeals to real lesbians (and actually they can find it kind of frustrating to have their sexual orientation played up as titillation for straight men rather than something that is authentic.)
In terms of titillation as entertainment, there is a space for that in the world, sure. I just don't think that space should be 'most or all games', and I think people like Bioware are good to have in the industry because they go out of their way to provide characters designed to appeal to a lot of different groups. Fanservice is fine, but spread it around to everyone, and don't use it as a crutch in place of other ways to hook people into a game, like good writing, clever puzzles, inventive mechanics, etc.
I also think that any benefit people might get from titillation (or anything else) needs to be balanced against possible harm it could do. I could tell a really offensive joke about, I don't know, dead babies which would get a laugh from some people and thereby make me feel amused and satisfied. I would say it's not really worth it though, if doing so would seriously upset people listening - in front of one of my friends who actually did lose a child to brain cancer, for example. My few seconds of laughter is not worth the price of their pain. Likewise, I think that a lot of games would not really suffer from reducing the titillation factor, and would gain from expanding the potential audience and not alienating any players who will feel demeaned by it. That's even without touching how even small measures of information, like memes, all shape culture and attitudes as well as reflecting them; so by trying to be more inclusive in media, we can help (slowly!) make the world that little bit more inclusive by normalising ideas.
I have not and would not claim that anything or everything I personally dislike is morally or inherently questionable. I would counter that assuming that everything you or I like or enjoy is inherently above reproach, either. It's ok to like things that are not perfect, and to acknowledge their problems while still enjoying them. I'm struggling to word the other point I want to make here, but basically, a lot of the things that people find objectionable in games are things they also find objectionable in meatspace. So pushing back against them in games is not just some kind of petty anti-game agenda, it's pointing out an example of ideas that can be or are harmful in a real way, and saying, this is the kind of thing I'm talking about. I think it's worth taking those kinds of criticism into account - not just swallowing every random critique every random person has at face value and then self-flagellating, but consider it, weigh it up, be mindful of it in the future.
As far as sexualised vs sexy goes, I don't find sexualised to be as much of a subjective term. I think it's usually pretty clear when a character has intentionally been sexualised - for a start, their creators normally will acknowledge it one way or another, that physical appeal to a certain subset of the population/demographic was considered. (Or in the case of my Baldur's Gate example, it was just self-evident; the tavern woman's physique was rendered completely differently to the female player character model I was using, and the camera angles and gratuitous bouncing made it overkill. Man that was nuts.
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Anyway as you say, there is not likely to be any kind of agreement on this, and I need to go to bed in any case. Hope everyone enjoys the rest of their day.