@Kanic,@ lolwutfool - ok, my bad.
@Candor, but we probably won't see explanation about this fight because that's Kubo style.
For example - Kensei vs WonderWeiss - for Kubo that fight never happened, Kubo didn't even bother to show defeated Kensei(like in the very current case with Rose). And when we're at it - we were shown Kensei's bankai - but aside from its uninspired look we don't know anything about it(how it works and why it was so useless against WonderWeiss).
Or more important stuff - we only see the beginnings of Ichigo's training and then the results. Or how about this big ass-pulled hollowfication in the Ichi vs Ulquiorra fight.
And to discuss your points:
Byakuya - he was defeated with something reasonable, fear from losing Rukia and he was hit 3 times with his Bankai, I see no reason for not remembering that part, we still don't know if he's dead or not.
Byakuya was defeated by some random dude(no backstory, nothing) who then got killed by Yama. So i guess epic re-match is no longer possible.
As for the "dead" part on Byakuya's side - come on, this is Bleach* ;].
Yamamoto - That's where I said you're rushing things here, he was trying to end the battle quickly and he raged over Yojiro's death and was underestimating the enemy and he was outsmarted by Bach, but we know no further info, wait until things get explained fully.
But it isn't usual Kubo's "ambiguous" ending in which he really sucks(for ex. Aizen and his countless "deaths" at the ends of the chapters in fk). It really looks like the end of the fight. Granted, its only my(and apparently Hanyuu's too) impression, but I think we are not the only ones who see it that way, and for valid reasons.
We talked about these chapters, I thought that this is only the beginning of their clash, you also hoped that Yama"'ll put a good fight".
Kenpachi - We still don't know what happened and who defeated Kenpachi, is it FBach? is it the blondie and FBach did the finishing blow? Again you're rushing things.
And we probably(but in this case there is a chance for us to be given explanation since Kenpachi isn't the one to accept his defeat without some words, so we might get some insight of this battle later - but that would mean some character developement, not the strong side of this series) won't know which is even more depressing x/.
Oh, I remember the exact same situation like Bach vs. Ken = Ichi vs. Ulq - when Orihime got to the upper level, Ulq strangled already defeated Ichigo with his tail and held him in the air.
Like Kenpachi & Byakuya vs. Yammi, the strongest Espada(my ass) why bother to show it, right, Kubo?
*Though I would really like to be proven wrong in this case. I don't have anything against Byakuya, but his death would have some major impact. For now we're left with the death of the character who was a joke for the entire series(Sasakibe) and couple of no-names.