Mimi is LITERALLY what most people would look for in a girl. Ryuichi is mid as hell for not choosing her.

Her tsundere will never end like no tomorrow, lol. Ironically, he knows it but still tolerates patience without compromising his confidence.

I like how he knows she's a tsundere and is actually sick of it

I personally would have chosen Mimi.  I KNEW a girl like Niko for 6 years.  She kept insulting me every chance she got.  I put up with it because she was part of the group, and she actually was kind of fun to hang out with when she wasn't being mean to me.  She eventually came clean and told me that she liked me, but I couldn't reciprocate her feelings because my image of her had been irreversibly damaged from all the insults.  I don't like girls that are mean to a guy and just expect them to figure out that they like him.  I prefer honest and kind girls.  Tsundere's are one thing but what Niko was doing went beyond pretending not to be into him and was just constant verbal abuse.  
BTW, the 6 years were from 5th grade to 10th grade.  she moved away after that.

Story Idea:
An adult woman (FMC) receives a wedding invitation from her childhood friend and her first love(MMC) who she hasn’t heard from since high school. The reason why they cut contact was that she was a tsundere that teased yet loved him, but he finally had enough and stopped talking to her. She tried to talk to him but he always ignored her like she didn’t exist. He then left to a university far from her and now she learns that he’s getting married. After the wedding, she goes home heartbroken that because of her attitude she lost her first love. When she falls asleep she wakes up back in her high school days, before he cut contact with her. Taking an advantage of this event she vows to change her attitude to become a better person and to not lose her first love again.

An after-story for those who don't like the tsundere ending:
Not long into the relationship (about 2 to 3 months max), things return to the status quo of Niko constantly insulting him for no reason even when he's trying to do something sweet for her like give her a gift. So this time, he officially cuts all ties with her and stops associating with her. Making it known to the school why he broke up with her so the rumor mill doesn't get the wrong idea and start blaming him. Seeing an open opportunity to defeat her rival and gain MC's affection, Mimi comforts him during his recovery from being around Niko and slowly worms her way into his heart by showing him what a healthy friendship is like. Eventually, the two do get together and have a much healthier relationship. Niko tries to come to MC, saying that she's changed for the better and gotten over her harsh tendencies, but MC has already moved on and wishes her luck finding someone else.

Even though he knows that she was just being a tsundere, I'm still shocked about him not running out of patience completely and just cut ties with her for real. Up until the end she was still annoying as heck, he even admitted it himself. One of these days her tsundere attitude will get worse that the MC will soon regret not choosing the other girl, but I hope it won't come to that.

3:44 - This. This right here. "It's always peaceful when she's not around." "I'm having the time of my life." He's happier without her than with her...there's even sparkles around him. This should tell him everything he needs to know about his childhood "friend" and whether she's a good match for him romantically.

Sorry, team Mimi here. I've been with a girl like Niko before and it was exhausting. Constantly having to read between the lines, and listen to abuse even if they dont really mean it,. It just gets overwhelming if you always have to be on the defensive. Much better to have a partner who can be supportive of you and the relationship. Trust me, find a person who makes you want to be a better person not just for them but for yourself too. You'll be so much happier in the long run.

This has the potential to be a what if story. One route where he chooses his childhood friend, and the other route where he chooses Mimi, besides he was already beginning to be attracted to her anyway

Even though Mimi lost to Niko and didn't win the tickets to the amusement park to go to with Ryuichi,😢 it's nice to know that she's not giving up just quite yet.🥲

This is why you should never go down the route of teasing your crush because no matter how much of just a joke it starts as, you may cause your crush to start believing the jokes partly because jokes usually have to stem from somewhere and eventually they will get fed up with you just like ryuichi did

ABSOLUTELY DISSAPOINTING HE CHOSE THE CHILDHOOD FRIEND OVER A GIRL WHO IS PERFECT IN EVERY WAYS cmon man damnit

Finally, an MC with a backbone who doesn’t take crap from every harsh word his “childhood friend” says to him.
Edit: Or not.

If a girl treats me that way and can't be honest with her true feelings, I would never go out with her. I don't wanna keep on getting hurt every single day

8:35 My man Kawamoto is happy to escape the inevitable drama.

Why do they always end up with the cruel childhood "friend"? Neither side deserves that.

What the hell, Kanon?  You had the makings of a story that would set you apart from all the other manga channels.  An MC that wasn't only genuinely fed up with his childhood friend's tsundere attitude and mistreatment of him, but was willing to act on it and tell the friend "enough is enough!"  An MC that realized he didn't have to settle and had enough awareness to see he had actual other options.  The story even has an FMC who is HONEST WITH HER FEELINGS TOWARDS THE MC!  I mean, how often do we see that??

Why did you throw that all away?

I'm not the only one saying this.  It's pretty clear from the comment sections on these kinds of stories that viewers would love to see something like that.  It's clear you can write and act that sort of story - you just have to follow through.

How I wish he would choose Mimi and dump that silly, annoying, immature and rude excuse for a girl!
Girls like that deserve a Little humiliation and a good cold shower of reality.

I like this story idea

The childhood friend or friend of the MC annoying the MC until the MC cuts ties with them. I would like to see more of those stories on other manga channels tbh