One of the biggest things I dislike about 99% of NSFW content is how lazy or insincere all of it is* - often times both. It's not necessarily a matter of taking itself too seriously or not (after all, I think humor can be an essential part of most any setting, and it can come in many different flavors), but rather coming across as a complete and cohesive creative vision that allows the person experiencing it to mentally engage with and become lost inside it. DoL was very easy to get attached to because of an expansive amount of consistently interesting writing that works very hard to flesh out its world, but also because it doesn't resort to all the quick cliches and writing shortcuts that most everything else does. Even when DoL does make use of tried-and-true conventions/archetypes, the game approaches them with both enough effort and sincerity that the game owns it and it works. I can't say the same is true about hardly anything else out there, where even a single glance at how they present themselves is enough to tell you that they just don't really give a shit.
*Actually, I'd honestly say that this problem also applies to a majority of non-NSFW content as well, but not quite to the same degree. With NSFW stuff, there seems to be this completely overbearing thought that as long as it looks good, then nothing else really matters, which I think is an unfortunate mentality for any medium of art. You don't really see the same kind of thinking with books ("as long as the author's prose is good, nothing else matters"), music ("as long as it sounds good, nothing else matters"), movies, or games. Like, yes, the most basic element of each medium is very important, but there are also other things to consider, like world, characters, story, themes, framing, tone, style...and others, as applicable. Each medium has its own strength and limitations, but they can be surprisingly versatile in what they can accomplish given the right creative minds, and NSFW works shouldn't be any exception.