I was in the middle of making another post but forget that. More important ideas occurred to me while in the process of articulating the old ones.
Let us consider that Kabuto is a stand-in for Tsunade in Orochimaru's eyes. Of course, Kabuto is much more subservient to Orochimaru than Tsunade ever was or would be, but just stay with me on this. Both are medical ninja, like generationally gifted savants in their fields. Both are excellent scientists in a broader sense, and work well with Orochimaru. Orochimaru has always depended on having a medic nearby, not just to attend to their own wounds, but also to assist with experiments/stop test subjects from dying. Orochimaru employs several medics for this reason (eg Karin).
Anyways, I just think its so interesting that Kabuto fills the niche of "medic who I rely on for strategy as well as friend and confidant" which Tsunade almost certainly occupied before she left the village. Like Orochimaru really went out and found/made another Tsunade except this time made sure the new one worshipped him and could never ever leave. Which is of course ironic because during the 3-way deadlock era Orochimaru spent all his free time acting like he didn't gaf about his teammates and pushing them away. Only to go off the deep end and sign up for Root when they both did in fact leave.
All well and good of course but this opens up an even more fascinating possibility: Shizune is Tsunade's Orochimaru replacement.
Think about it!!!! We have long been asking the question, who are Shizune and Tsunade to eachother, and why are they like that about eachother? The most obvious thing connecting them *should* be Dan, but Tsunade and Shizune literally never bring that up unless they have to. They're also master and pupil, but Shizune is grown up and has learned all she ever will from Tsunade and is just still following her around and helping her.
Consider also Shizune's skillsets: Yeah she's a well-trained and competent medic, but her combat style is nothing like her mentor's. She has this whole thing with poisons especially, which is *not* something Tsunade does. I mean we can assume she has some skill in it, but mostly she's known for nullifying them. We never see her use them offensively. Yknow who does though? And lets talk about Shizune's pragmatism. She's not afraid to go behind Tsunade's back if she thinks its the safer move. (See her trying to convince Naruto not to go ahead with the rasengan/necklace bait, ratting Tsunade out to the councilors about letting Naruto go on a mission.) Hot take but if she was in that cave surrounded by enemies with Tsunade and a third dying teammate, she would've done the same thing Orochimaru did: told Tsunade to give up on the injured person and escape just the two of them.
Tsunade went out and found/created a pragmatic ethically dubious scientist to replace Orochimaru. Except this time they're completely devoted to her, and would follow her anywhere. Which is ironic because when Tsunade left the village she was rejecting the ninja lifestyle and wanted to be left alone to rot, and didn't want Orochimaru to follow her.
IMAGINE YOU WERE GROOMED SINCE EARLY CHILDHOOD BY YOUR TRAUMATIZED AND WEIRDO MENTOR TO BE A PERFECT VERSION OF THEIR EX AND YOU'RE PERFECTLY FINE WITH THAT BECAUSE IF YOU CAN JUST BE BETTER THAN THEIR EX YOU'LL BE IRREPLACEABLE AND INDISPENSABLE AND THEY'LL NEED YOU FOREVER