To represent the experiences of those less often portrayed in particular artform is a noble goal, and 90% of everything is, of course, crap. Material intended for consumption by a particular niche group is likely to appear unusual to those outside it. Low production values, while obvious to those uninterested in the work, may be overlooked by those who are sucked into the story. Looking back, Katawa Shoujo's a lot more rough round the edges than I remember it being when I first played it at 15, but the slightly wonky art and cut corners didn't register because what I liked about it blotted it out. It's very easy to sneer at jank, but I'm fairly certain if you're reading this there's something you like even though it's rather badly made. When you're far enough outside something's target audience, trying to judge it becomes pointless.
I find that if the "jank" as you aptly put it doesn't detract from the experience, bemoaning it is an academic, sterile way to think about the game in question. Some things are best enhanced by their flaws.
But I have to push back from your first point a bit. I don't think any game is portraying the experiences of anyone from real life unless you're playing a very boring game or the person in question is a serial killer or psycho or something weird and uncommon that most of the people who claim they feel represented by a game definitely are not.
Also, compared to the things these games DO represent, whether someone is black or gay or anything of the sort pales in comparison. Compared to playing as the goddess of the sun who paints creation and it flourishes into existence through her will, what is it to be gay? It's but a brushstroke, there, she just cut you in half and blotted out your existence altogether while yawning.
I think an over-reliance on realism and an ignorant perspective that fails to see what goes on in the context of games is serving to limit our perceptions of what we are really depicting in games, just how beyond any real person most of it is, and that the value to be found therein is directly linked to that separation from the ordinary, to that exact lack of representation people bemoan.
I don't wanna play as a represenation of myself, I wanna be a fucking dragon that flies in space and has giant diamonds for wings dude.