Concerning the whole harem vs no-harem debate, here are my points towards this topic:
Pro harem:
Let's be honest guys, at the end of the day we all just want something to fap to or to live out our fantasies, what better way than to have a group of our personal favourite girls - especially when you just can't decide who you like more than the rest and don't want to be burdened with breaking some of the girls hearts (even if it's just digital and all - you may be invested into some characters).
Con harem:
For a harem to function you would have to find a way to suddenly make every single girl incredibly obedient or compliant af (looking at you Katie!), so this would in return bring in some stupid plot twist or something like that (or we may see a good plot twist, which would be unlikely in this scenario).
So yeah, in the end it's either more to fap to in favor of less coherent plot or better plot with only a single lady in each route.
As for myself, I have been burned out harem endings after finishing Lust Epidemic (really a loooot of orgies going on in this game).
Also, the plot in this game is actually really good, even if it may not have the best writing all the time.
It would really tone the game's quality down, if you had established characters who were stern about having monogamous relationships suddenly be cool with sharing their partner and be free-for-everything, this would really make this come out of nowhere.
Since there were some characters I couldn't really sympathize with, I made sure to not bring them into the equasion.
If the permanent decisions arise, I will make multiple saves to choose the routes of my liking.