Metatropes
Blank Slate
So, you're writing a game and you want your players to be able to map onto your MC? How about making them a blank slate? A teenager with no skills or value to any of the women around him, a 40-50 year old with no life and a boring ambiguous office job? That's right, your main character could easily be whatever the Player brings to them... but wait...
Relationships are give and take and your MC has nothing to give, and also, the only thing they want is sex. You see, the flaw of your MC being a blank slate now bleeds into the rest of the cast. 1 dimensional characters become the norm, they'll have 1, maybe 2 defining character traits and you'll exploit those to get what you want, sex. A greedy bimbo uses you for your access to money and other things she wants. A shy and quiet nerd has an inexplicable crush on you that you just kinda need to be there for. A doting mother just needs to see your cock, or worry that you can't handle your erections yourself, and she'll quickly be hypnotized into more. Not to mention the dirty, underhanded, and downright sex pest-like behavior that will get your rocks off until they are willing to do it without your criminal behavior. Because that's all these characters are, sex toys with simple personalities.
With one decision, you've written an entire game that is barely any different from watching porn. In fact, in many cases, porn is better since it's easier to get.
The good? - Echoes of Lust, Babysitter. EoL has all these problems, but the introduction of the fun groundhog day mechanic adds a layer of intrigue to it that makes it fun even if you've played it a million times with all the other blank slates. Babysitter took the time to flesh out their blank slates as the game moved on. It started out no different from Dating my Daughter, in terms of construction, but found it's own place with well rounded characters.
The bad? - Big Brother (I know you probably wanna see it in fugly but this trope isn't about Eric), Summertime Saga, Cure my Addiction, Milfy City really so many others. What BB and CmA do is put at least a little effort into making the characters themselves fun, nowhere near as much as Babysitter did, but at least to some extent. Summertime Saga is about half and half at this point. My recent replay has shown that there's a lot more thought put into characters like Eve and Roxy, as well as a little more skill put into characters like Jenny. It still suffers a lot from it's MC being a blank slate, but it at least gave some of it's cast depth. Milfy City seems to have taken a cue from Summertime Saga, it's trying to shake up the narrative, mom and older sis are completely different from the normal bitch older sister and doting mother, but at the end of the day, while it's shaken things up a bit, it's still not great.
The Fugly? - Dating my Daughter, F.I.L.F., pretty much any RPGM incest game, Man of the House, and so many others that aren't worth listing. These games either make progression pure grind, or they are just writing the blankest of slates and making getting in their pants more of a chore even if it's easy. There's no fun in this, and even the porn itself loses it's value to you because you have better shit to do.
Blank Check
Your character is rich or at least has a very easy way of making money, good looking, and knows exactly what to say at any given time. He's not particularly interesting, he probably doesn't have a 9-5 job or any specific hobbies, in fact, he's kinda a blank slate except for the fact that in his case, it's all too easy.
Maybe you inherit a lot of money when a family member dies, or maybe you invested and won big during a major economic boom, maybe you made something in the past and don't really have to work now. Or maybe you have a roof over your head regardless, and so whatever simple thing you do, you do it freelance and without any deadlines. This financial freedom and lack of any obligations frees you up in a major way to sate the one desire you do have, getting laid. You are literally surrounded by pussy, and if we're being honest, they all already want to fuck you, they're just holding back because they've been taught that it's the only proper way to behave.
And so, you spend your time with them, or on them, as need be. Maybe they express desire for something and you make it happen, or maybe they need advice and you know just what to say. Regardless of what it is, you're the solution to all their problems, and this constant ability to solve their problems makes them more and more likely to give you that sex they're already begging themselves to give.
The Good? - Harem Hotel, Mythic Manor, Offcuts. These games make do with your blank slate, surrounding the main character with girls who have their own problems and desires and giving you the push to help them work through it. Harem Hotel manages to make people tear up over some of these girls' experiences, and makes you genuinely want to help them. Mythic Manor doesn't quite get that good, but regardless it makes you feel like you're accomplishing something while not making you grind your ass off. Offcuts has a genuinely entertaining story with characters who are absolutely well written, in spite of being no one, you've been given a blank check in regards to these girls' affection, you just have to make sure to cash it.
The Bad? - Parental Love, My Sweet Neighbors, Sisterly Lust, Acting Lessons. These games aren't "bad" but in their attempt to differentiate themselves from the grind of DmD, of which they're kinda clones of, they created these Marty Stu MCs who really just have to be there to get sex. Sure, there are different routes in them that have some sense of consequence, but is it really a consequence to not get to have sex with a character you don't want to have sex with? I enjoy or used to enjoy these games, and they aren't as bad as some of the Blank Slate games with 1 note characters, but they're not much better either. Acting Lessons specifically has a huge problem with tone that it simply couldn't nail down, it might have made it to the good list had it not had no idea how to use its antagonists.
The Fugly? - SolValley High School. This one doesn't belong in the blank slate, because he actually has something more to him, and while he starts out with low stats and a need to increase them, there's nothing stopping you from grinding his job till you get them and then just playing the game as if you were independently wealthy. Once you have his stat boost items the game is simply a buffet of girls waiting to by hypnotized by his giant cock and asshole attitude.