I know I have some flaws as a writer, and I have seen some of the complaints from you guys and I have apologised for it. But here I will be debunking and explaining the arguments that are just plain dumb.
Why is the Mc so useless?
Imagine getting killed all of a sudden, barely getting over it, get reincarnated into another realm with no clue where your supposed to go, get confronted not just by one but several of the things that killed you in a previous life, and you end up walking in on them beating up a child. Don't kid yourself, you'd be pissing yourself just seeing a hollow IRL. You are not the absolute Sigma that is Chad.
After seeing how useless he was which he admitted, he made up his mind to fight hollows not just to find his father, but to stop people from dying the same way he did.
Someone complained about Kai doing ass in school, that was honestly meant to be a short gag, but at the same time, he's competing against students that have been learning and training to get in months-years before he did. It makes sense he hasn't caught up yet, and it paves the way for the next arc.
Now near the start of volume 2, I admit I partially messed up here. Kai gets scared of a giant hollow, and Yuki saves him. At this point its his first real combat against a hollow, and any normal dude would be scared shitless too, but this isn't Kai's first encounter with one, so he should be used to this, right? However I didn't write it that way, and that's because I wanted to set up a plot point in the future for this which I haven't gotten too yet. That fear appears a little again in volume 3 as well, but I apologise for writing it like this.
But my gripe that comes next is that people say he hasn't grown or changed. At the end of the volume 2 he takes his first real step to becoming a soul reaper, by fulfilling a foundation which I've referenced in a previous chapter, that's even canon to the main bleach.
"A Shinigami should give his life to protect his friends and humanity."
We see this fulfilled when Kai tries to protect Linny from Akimitsu only for the opposite to happen instead. In his inner world we see him despair. He had changed, it's just that no matter what he did, he couldn't keep up with those around him. This is where I started to build up his relationship with his Zanpakutō as it offers him not just a small portion of its strength, but a little of the power he unknowingly used in district 64.
At the end he wins the fight and even kills someone. But it was far too late and Kai still blames himself for it.
At the end of Volume 2, he understands what it truly means to be a soul reaper. He realised that his weakness comes not from him not trying enough, but the lack of his ability to understand why others fought. His battle with Akimitsu was really more of a clash of ideals then a literal battle. He fought to protect Linny, but it wasn't until she died that he fought to get revenge. I kind of wrote him to be an opposite of Ichigo who fights to protect while Kai fought for retribution against the week.
Why is everyone else so useless?
If this is a complaint about Ichigo, it's already been established what he's been doing at that point. The entire reason I created Yukiko was so that Ichigo wouldn't be there and erase the stakes. When I first started planning vol 1, I originally intended for Kai to die by Ichigo's mistake, but that didn't make sense so I wrote him out for Yukiko.
And as for Uryū, he was in another city. Even then, he beat up the reincarnation of Yhwach single-handedly, and came out without a scratch. Although I haven't made this more apparent for some people, it was thanks to this encounter that Urahara now knows of the existence of characters like Sakugo and Albrecht. More anomalies like them are going to appear more in the future.
I wanted to give characters like Ginta a chance to shine in Volume 1, since he won't really get any opportunity's in the future. And then the events in Sugishito take place in like a day and a night. Not much room for Bleach main characters to appear out of nowhere and save the cast.
Essentially, your bitching about your fav character not being in a place they can't even be.
If you have any other complaints, feel free to talk about them here. I'll respond to them properly rather than just apologising or ignoring you.