Unfortunately I cannot give any spoilers about the story
I understand the desire of creators to keep quiet about what their games are about, because they want to avoid spoiling early surprises, twists, or giving away too much of the plot before the player even starts.
The problem is, it makes so many game descriptions utterly generic, to the point where the descriptions kind of become useless. When every game is basically described as "This is a game! You will get to make choices! There will be people you can have sex with, and stuff will happen!", there's nothing that really stands out from all the other games that describe themselves the exact same way. And worse, it's a redundant description because we already know all those things implicitly when we see a Ren'py game being posted on an adult game site with screenshots of naked people (or genre tags that tell us sex will be happening).
I feel like even a
little bit of extra info can go a long way towards making a game stand out and making people interested in playing/supporting it. Is it a light-hearted game where you're mostly just choosing who you want to screw? A psychological drama where characters will slowly come to terms with past traumas? A goofy buddy cop comedy? Is your neighbor secretly a vampire? Are you eventually going to become an action hero and explore ancient tombs? Is there a sinister conspiracy that the MC has to fight? Is the MC's father dead, and there's probably a mafia somewhere in town (aka the standard AVN package)?
There are definitely ways to give a little bit of extra spice without having to give the entire plot of your game from start to finish away. Even "You've inherited a hotel and are going to use it to assemble a harem of love interests" (cliche as it might be) tells me more than "You will make choices that will determine the ending!"
I mean, Choose Your Own Adventure novels didn't just say "Hey, you can make choices and there will be multiple endings!", they'd also give you a little back-cover blurb telling you "This is the one where you're a spy!" or "This is the one where you're a treasure hunter!" or "This is the one where you start a rock band!" or "This is the one where you're a ninja!" or even "This is the one where the writer was
really high on LSD when he wrote it!"
I'm weird at playing, and without the possibility of a harem I'm not likely to be interested in a game: I'm very unlikely to play again, so I prefer to be able to be with all the LIs that interest me in the first game (and have a unique ending to them).
For me, I don't mind the lack of a harem ending so much, so long as the game either makes it
very clear you should focus on one girl over the others very early on (possibly before you start playing), or at least allows you to pursue multiple LIs early on but then make your choice of which one to dedicate yourself to later without having all of them dump you for cheating. Or having the ones you break up be utterly devastated and emotionally wrecked because you didn't choose them.
I'm also not a huge fan of stories where it's implied that any girl you don't do the romance route for winds up miserable and alone (or worse) without you. I think an ideal game for me would be one where you can "friendship route" any girl you don't romance, so you can still help them out with their issues and get them a happy ending even if you're not screwing them.
Though along those lines, I'm also kind of annoyed by games that either start you off in a relationship or force you into one early on, so the first girl you see becomes the "canon" love interest, and the only way to date anyone else is to break their heart or cheat. Especially if the first girl is relatively sweet and loveable - it's a lot easier to justify kicking a bitch to the curb than a sweetheart. I think the ideal set-up is to have the MC start out single, introduce all of the LIs early, and only start giving the options to seriously pursue them once the player has a clear idea of what their options are (and the consequences - ie, whether harems are possible, if dating more than one girl will piss all of them off, etc).
Though it also depends on the genre. If you're playing a corruption game where you're breaking every LI you come across, harem ending feels pretty much necessary.