Harem tag is purely about variety. Hitting the widest possible audience. Imoupara series, 3 in this case, is harem and has;
Sakura: Pink hair charcter, long pony tail, largest huge boobs, motherly, sugary sweet, serious about taking care of her family, loves to make love, a little lewd, will take it in the kitchen
Hiharu: Orange haired character, short side tail, large huge boobs, just under pink hair sister, sporty, tomboy, not very serious, funny, lewd, will use her pussy to win a competitive video game with mc
Rika: Blue haired character, short twintails, small boobs, big ass, tsundere, loves getting it rough, kotowari play, very serious, likes to study, not very lewd but is kinky, likes to be dominated
Hinata: Blonde haired character, long straight hair, small boobs, small body in general, very inexperienced character, sugar sweet, not too serious, wants to learn, lewd later on in the story, will go full catgirl
Zakuro: Black haired character, long straight hair, medium boobs when compared to the other sisters, still big though, wants to dominated the MC, seductive, extremely lewd, playful, will give mc a hand in public, that's not an option
Did any of these characters hit your strike zone? Some hit mine, some missed. The story is mc gets it on with his sisters, please note in this fictional world this is completely normal. There are some cute and funny skits in between the content, but its basically nothing. Nekopara doesn't do this, it has a nice story with a bit of drama in it, in between smashing the hips and boobs of catgirls. Though mostly the harem genre does not have much in the way of story and is mostly just an aid.
It's just not serious enough for real world sicknesses, deep drama, and negative personalities. There are exceptions, far more so in harem VNs without sexual content.
To bring it back to APBLU, the harem genre is fairly lacking in dirty, sloppy, nasty, cheaty, rapey, for one parties' pleasure only sex and all the drama that goes with that. I gotta say, I do like it when HC uses comic relief in the story, more than I thought I would. I little harem style humor in a seriously crazy story.