The final chapter would be the one where IchiHime and RukiRenji were revealed, where we met the children of both couples, where we see Ichigo take over the Kurosaki Clinic, where we see Chad has become a famous wrestler, and where we learn Uryu has become a doctor at his father's hospital.
So, that's great, but that has nothing to do with the plot points Kubo started or dropped anywhere between the first chapter and the last chapter. We pretty much just know Kubo never planned for Ichigo and Rukia to marry based on comparing those chapters.
And that's just your assumption, not a definite one. There is no evidence saying that IchiHime and RukiRenji is only plan which Kubo had since chapter 1. Nobody exactly know how much Kubo actually planned on the final chapter. Heck, there is still high possibility on Jump axed Bleach because of low ranking (and many people are still very well of that). There is no actual evidence saying that his health issue in ONLY reason.
He actually did go over how he used to have infrequent bouts sickness that became so frequent that not even a week in bed helped him recover. He said his sickness was so severe and lengthy that it made him under-perform in regards to quality and timeliness. He said it made him feel like a failure of a mangaka. So, yes, he was sicker than he was before and it was interfering with his ability to work.
By the way, you say "cold" as if that proves it was minor. Seasonal allergies can knock some people on their ass and the flu kills people, in America, every year. What you experience when you get a cold is not the same as how everyone else's body reacts.
There were two breaks during the 1000 Year Blood War arc I can remember. The break where The Dagger was released that summarized the arc so far and then the break before the last stretch of the manga. IIRC, the second break was when The Separation Story was teased. Those breaks would be opportunities for him to rest in addition to the double issues he mentioned where he would get a week off.
And do you think other authors don't get sick as well? Many other authors do get sick, like Sorachi and Kishimoto took absent because of illness. And I'm not just talking about like taking one or two absents in every couple of years (I checked and Kubo very, very, very, very, very, and very rarely take break (this trend still continues even during the final arc, as well)). If you saying that just taking one or two absents is a sign of author is having very serious illness which going to impact on the series' fate, then are you also suggesting that Gintama and Naruto ended (and going to end) because of the author's poor health. Just taking one or two absents within couple of years isn't a sign of the author having serious illness.
Since you're saying Kubo should had serious illness, then do you, honestly, think these serious illness can be healed like within a week or two? I doubt that.
Hoshino took couple of long hiatuses because of her illness on the neck; Togashi took long break because of his back issue; Inada Kouji took like 10 years break of his serious illness (never explained what kind); Morita Masanori took hiatus due to poor health even near the end of the series; and now, Ashihara started to take indefinite break now because of spondylotic radiculopathy. Do you think those authors' illness are serious enough to deserve long break? If you think Kubo is experiencing same illness as them, then why not Kubo getting a hiatus? Isn't Kubo's illness serious enough to impact on the series' fate, itself? Are you suggesting that WSJ editors don't like Kubo and forcing him to keep serializing it?
So far, Kubo didn't get like very frequent (like actually getting absents every couple of weeks like Ashihara) and I don't see his illness being as serious as those people. I do understand that he did have poor health condition, but it isn't actually serious enough for Bleach to have sudden ending. If it was truly about his health, then the editors should made him put rest, not forcing him to do work, like those authors.
The tweet doesn't plainly state why the manga stopped early. Likely because it would be viewed as unprofessional for him to discuss this publicly.
Though, you have to ask why he would mention his sickness at all, let alone with such detail, if it had nothing to do with the manga or its end.
Firstly, that is just your perception about discussing the series' end is unprofessional. There are many authors who explained why they decided to end the manga. And I didn't see any criticisms on that issue. Plus, we don't know if Kubo think this is unprofessional since he never made any comments relate to that. So, we can't just conclude Kubo may think that way.
As I said before, the main reason for this short manga is to say thank to that fan who brought great support to him. Since he put up in his twitter means that he want to share his experience and appreciation to many people. He wanted to fully show what kind of difficult situation he was and how this fan supported him to overcome his struggle.
Do you actually expected Kubo to just release the photo of those letter and just end with it? And do you think it was just waste of time putting the material? You think that material is unneeded in order to explain why he able to overcome his struggle?
Remember, this "appreciation manga" (that's what Kubo wrote) is fully dedicated for that fan, not to us. He put it up on the twitter in order to get more information of that fan and able to give it to the fan's grave. And do you think Kubo needed to explain why he ended that way to the fan?
Edited by Negative Syndicate, 17 November 2016 - 10:48 PM.