Barbelith Underground > Film, TV & Theatre

On the first point, translations differ. The one you site is the Dattebayo fansub, the scanlated manga I downloaded (translator unknown) opts for "You've never addressed me like that before," which might be a reference the honorifics - or lack of - applied by Ryuken. I don't believe this issue has an *official* translation yet, but I'm also not sure that Kubo speaks or reads English so I can't say whether that would be more accurate to the meaning or not... especially considering that it might relate to a story point that doesn't exist for us yet and that Kubo might not want to spoil, even with the pretty slim possibility of it being leaked by translators.

Ah, Bleach. We'd have less trouble annotating the Bible. All we can say for sure is that Ryuken has let slip something about a possible change in the nature of their relationship through how he has addressed Isshin.

As for the loss of Isshin's powers, we can speculate that he's been wearing one of Urahara's gigai, got his Chain Link and Soul Sleep severed, transferred his powers to another person in the same way as Rukia does in the first issue/episode or was stripped of his powers as punishment (that's a mini-spoiler for something upcoming in the comic, forgiveable in that it tells you nothing... I hope). Those are the only ways of losing your powers that we've seen besides the one-shot-blow-your-wad-in-one-go thing that seems uniquely Quincy. Lethality Stone also does the Forge/Storm thing but we can discount that as no one else in Karakura Town has any trouble using their powers, and the only other way of limiting power that hasn't yet been adapted into the anime is similarly not likely to be the case as it also relies on enclosing the subject in a single geographical location, and we know that Isshin moves around.

Ultimately, the inclusion of these elements into Bleach so early is a massive tease because we're not likely to find out the real story for absolutely bloody ages. At which point I have again offered a spoiler for the anime, because you can infer that it hasn't been explained in the comic yet, either. Essentially, no one knows any of the backstory yet and we really don't have enough material to speculate besides being able to say (based on this one scene only, nothing that hasn't seen adaptation yet) that the relationship of the fathers seems a lot like the relationship of their sons. That plays out much better in the original issue, as it is split in half almost exactly, with Ichigo and Ishida bickering on the way into Hueco Mundo mirrored against Isshin and Ryuken bickering in the Quincy base with the minimal decor.