rampancy: Not trying to be confrontational (seriously), but it's while it's easy to typecast Japanese games as all being like Yandere Simulator or Rape/lay, we do have some arguably outstanding Japanese games like Crimson Clover and the Raiden series. I'd also count
Recettear and its companion game Chantelise in there too, if you're willing to get past the art style. That being said, in my own opinion I question GOG's decision to put up Hatoful Boyfriend and its Christmas-centric sequel, if they're going to use the "too niche" excuse with other games. (If you ask me, I think they were trying to chase a trend with that game being really popular with the YouTube crowd at the time.)
The Japanese game question I think applies especially to earlier questions about bullet hell/SHMUP games from renowned names like Cave. IIRC, GOG used the "too niche" excuse with those games, even though we have the aformentioned SHMUP games here already.
As for AAA games from big names like Sega and SquareEnix...for those games, I think it's safe to say that the ball's in their court.
Understood. Don't get me wrong, I don't dislike Japanese art, or Japanese art in video games wholesale. Just specific forms of it, and I don't like the way that a lot of the Japanese art inside or outside of video games portrays little per-pubescent girls as sex objects. I find that quite disturbing, and it seems to be exclusively restricted to Japanese art forms.
That issue aside though, the premise of a lot of the Japanese games I find quiet boring in particular the point and click type dating sims or the super crazy weird stuff that some of the games have which almost defy explanation. Some of the crazy stuff makes me laugh, such as Mr. Mosquito, but most of it is seemingly insane. But then I love Goat Simulator too so who am I to judge. :) The premise of that Hatoful Boyfriend game is just bizarre as hell to me. I just don't get how that could be appealing, but then there are many different genres out there and everyone has their likes and dislikes, and my personal choices for myself are no better or worse than other people's choices for themselves - except for those weirdo games that sexify 9 year old girl artwork etc. :)
Aside from those niche "weirdo" games though, big name stuff like Final Fantasy, The Last Remnant and similar I'd consider to be really on par with anything else out there and they have a distinct Japanese art style, just quite different in many ways from the stuff I find rather bizarre/weirdo. Likewise there are Japanese games that don't particularly have any specific Japanese art style to them, such as other Squeenix games like the Hitman series or Tomb Raider games. Of course we have many of those series titles here already too, but hopefully they'll bring the missing titles here some day as well. :)