Most dating sims I've seen seem to be made by people who never dated, or who did and didn't enjoy it so they fantasize over it - either on the sexual or the romantic side of things.
Then again, I probably played only 2 of them in my life and dropped them because I really can't stand the constant dialog, pauses, fades, out-of-place unnecessary stuff, and all that. I've mostly seen them on Youtube.
But what I like about real dating is the unexpected, surprises, and dynamic interaction. You're getting to know someone new, 50% of the time it feels awkward (which is always fun), and it can naturally feel really bad or really good for one or both parties.
As you said in the OP, dating sims suck because they are not "Sims" - most are just a weird multiple-choice exam in which, if you can guess the underlying direction, becomes easy to pass.
There's some game I saw which has some match-3 type mini-games. I remember that you had to be a good guy to some girls, a bad guy to some.. it was like choosing different approaches to different girls that liked different things. Maybe mix things up. At least on high school, that's pretty much how everyone would go about it, in real life.
I'm not sure how good or how successful the game is in not-sucking, because the dialog's still awkward, and with an american dub that makes me cringe (I don't know japanese, I'm not hardcore anime fan, but certain dubs can make things even worse).
But I remember thinking that was way better than the default "pretend you're a criminal"/"pretend you're a prince" kind of thing.
Still, I don't get it why those games are called "Dating Sims". With a fishing, flying or farming simulator, I can feel different degrees of the actual thing.
In Dating Sims, I don't think it will ever be any close to real dating. Not until we have sentient AI playing Human Simulator on one of their CPU cores.
Then again, that's not the point of dating sims, I guess - which, again, makes me don't get it why they are called dating sims.
Not sure if I added anything to the topic, because dating really is one of the games that I like to play in real life. Better graphics, better AI.
EDIT: The game I mentioned is HuniePop, but I now noticed I only watched Pewdiepie playing 2 minutes of it, so take what I said about it with a grain of salt.
I noticed it has explicit stuff in it too, so I don't know if it applies.