Let's also not ignore the fact that the feat can be lowballed to 6-A (actually it can be lowballed to Low 6-B if you only use the temperature statement to scale since that's a verbatim number),
You could argue for that. As I could argue for the opposite base on what happened to the floor once Yamamoto cut it with his bankai’s first ability, not the existence erasure one.
unlike the feat Aizen scales above (Senna's being Low 5-B+).
Aizen scales above this feat because a databook says he transcends everything. Which is not only proven not true when certain beings exist above him in power in the last arc, but is kind of vague given Senna is neither Shinigami or hollow. She is a strange phenomenon of nature.
Yama's feat is more dubious as to whether or not it's surface level or planetary, wherein WSK stability is very clearly planetary (assuming planet sized realms).
Both have the same amount of vagueness and evidence to argue each side as I stated above.
Bankai Yama = casual overtime realm bust that isn't even guaranteed to mean entire realm destruction,
A casual Yamamoto holding back not to destroy Soul Society. Intentionally, Yamamoto never went all out.
narratively hailed as the strongest in the Gotei 13 during his entire time in office
Correct.
Butterflyzen = stated to be WSK tier,
The same guy that was stated to not be a Soul King candidate because he wasn’t part Quincy?
multi-realm to arguably entire universal stability with the support of vastly outscaling the MoN multi-realm destruction feats,
The size of the realms is useless in this discussion as it applies to both characters.
narratively a god who surpasses Shinigami and Hollows and everything
I wonder if you guys will continue to scale Aizen to every single being that shows up in the future just because of an outdated statement. If Aizen was superior to everything - why didn’t he one shot Yhwach and went back to prison?
Feats Aizen wins, narrative Aizen wins.
Base Aizen feared facing off against Yamamoto and created an arrancar to seal his shikai. Base Aizen feared Kenpachi so much he trapped him in Hueco Mundo until he was ready to fight him after becoming transcendent. Same Kenpachi that Yamamoto feared would become even stronger and refused to train him. Yamamoto who is said to be stronger than Yhwach’s elite guards which includes Lille Barro a “God” confirmed by the God slaying sword of the Ise clan. Aizen been a God means nothing. (Hikone, Ginjo, and Ichigo aren’t Gods either.) Even the novels say Soul King isn’t a God, but a king, and
Gantenbainne even worshiped Barragan as a God with his cult according to Kubo. Base Yhwach was able to steal Yamamoto’s Bankai and was stated to be able to wield it. That alone supports his position as the strongest Quincy even in Base and able to defeat Gremmy in combat. The second strongest Quincy able to create worlds, stars, etc. Base Yhwach is already above transcendent Aizen and Yhwach even took precautions from facing Yamamoto’s Bankai like Aizen did against Yamamoto’s Shikai. Heck, we even have hints that Yamamoto and Quilge were transcendent. Just because you don’t like how it contradicts your scaling or the current VSBW doesn’t mean is not there.
Give me a scan from Kubo that says Aizen is stronger than Yamamoto.