Take a look at the book Charnel Houses of Europe: The-Shoah for Wraith: The Oblivion, that entire supplement is devoted to role-playing victims of the Holocaust. That is about as grim and heavy as you can get. No giggles or squeals in this game. It was produced for a mature audience, you do not want 3rd graders playing this game. So what? It was brilliantly done. An RPG can handle any subject and be paced for any specific level of sophistication, it just has to be written well and marketed to the correct niche.
I agree that a lot of what came out for Wraith represented attempts at an RPG being high art.
I also feel that as written, much of it was unplayable as a game, and that it would have been the rare group that could have treated the subject matter justly even if it was playable. Wraith therefore was less RPG as high art, than RPG book as high art where the game itself existed only in the abstract. I admire some of the books, but in practice what I saw of Wraith largely ignored the artist's artistic intent and well was a bit tragic considering the text. For that matter, I feel the same about Vampire:The Masquerade and the sort of 'supers in black' and 'Machiavellian politics as game' that I saw as typical of play, and the sort of adventures written for the game didn't help it at all.
One thing that I learned in that time was that some sorts of game play weren't suited for multiple players. The sort of intimate character dramas that a lot of the indy gamers/designers see as the primary hall mark of being artistic gameplay just aren't suited to more than a GM and 1-2 players, or 2-3 players in a cooperative story game. More players generally requires splitting the groups into intimate sessions. And one of things that I've discovered about that is that by and large, the format of PnP games gets in the way. If you need 'safe words' for your RP play, you've moved on from some sort of 'game' in a strict sense and you are engaged in role play as it is used on other contexts. What I find is that medium matters here. There are a lot of things I tolerate and find acceptable in a book that I wouldn't find acceptable in a movie. What seems necessary and appropriate in one, can seem gratuitous and artless in another.
Without getting into where I draw various lines, which is of course personal, what I discovered was that 'play by post' or MUSE play could approach some areas of content - say romance - with more honesty than it could ever be done face to face. The distance was necessary. I feel quite safe in saying that when romantic RPG happens in a high degree between players in a PnP game being played in a traditional format, the thrill is often real and the play is often proxy play for the real thing. In fact, it's often inseparable from the real thing. Two players playing out heavy romance in a traditional PnP format are pretty much almost inevitably playing out a real romance. I've seen it lead to real life marriages. Certainly this was often even true of MUSE play, but at least in MUSE play there was distance. Conversely, often where romance would be reasonable in PnP play, the lack of distance suppresses it.
By the time you get to the level of intimacy of erotic play, any distinction between real life and game play is basically gone. If you engage in erotic play in a game, it's pretty much impossible to have distance between you and the character. This is probably true even at the MUSE level (I've never tested that, but feel safe in the claim based on observation), but it would certainly be the case in face to face play.
By comparison with non-interactive medium then, it follows that when you are introducing erotic content, even at just the level of nudity, you are introducing a very different element to your game than exists in non-interactive medium. Medium matters, and therefore different social standards of what is acceptable are understandable in that context.
Leaving aside any judgment regarding Monsterhearts as a game, the fact that it is a different medium than the subject matter that inspires it, changes the subject matter. Watching Buffy the Vampire slayer, you can hold the opinion, "These beliefs and actions are the beliefs and actions of the not self, and therefore don't reflect my own emotions, which can be different than the character I'm observing." This emotional distance is much less easy to hold when you are asked to play the character in a non-pawn stance - which quite explicitly you are being asked to do - even if it were possible to play that sort of game in an entirely pawn stance (even GM would IMO have a hard time doing so).
Anyway, my point is that in failing to address the medium in question and in attempting to copy what works in different art forms, often designers with artistic intent end up creating game books that work as art in the medium of a sort of literature, but not necessarily games that work as art. IMO, eroticism as intimacy is a sort of crude short cut to emotional exploration play - the sign of a designer yearning for mature emotional depth he finds lacking, but not knowing exactly how to get there. There are plenty of adult subjects in for example, something like 'To Kill a Mockingbird' or 'Les Miserables', which don't require short cuts to achieving emotional reactions. Even something like 'Lolita', if you accept that as high art, achieves that result with a striking lack of overt erotic content. Sometimes a brick to the face is required, but if that's the entirety of your artistic palette, well, something is wrong.
And I'm not convinced that loosening standards leads to better art, but even if it did I think we can agree that there is a difference between studying Lolita as art, reading Lolita, and 'Lolita: the Role Playing Game'.
