You and I are normally on the same page, but not this time. I think this chapter was one his worst. It's not mass-resurrection bad, but not for lack of trying.
I actually thought of you when I was reading the chapter, figuring you would have a fairly negative reaction to it. 
This biggest issue I have with what you say about Karin is the same as before. Perhaps she is all those things, but if that's the case that is not the message he is sending or the character he is portraying. Seriously? She's embarassed to admit she likes Sasuke? Perhaps, she thinks none knows and I can't recall if she ever vocalized it to anyone. But, come on, she has to use the fact that he tried to murder her (and uses that word) as proof she doesn't like him and does so while (1) blushing and (2) in the midst of perhaps the most cliche' reaction in mordern entertainment when someone is called on feelings they think other don't know about.
The way I see it, Karin's exaggerated behavior made sense in the context of an argument with Suigetsu. It has been part of their schtick from the beginning -- he needles her about her fascination with Sasuke, and she denies it. It's nothing new. When Orochimaru questions her about her desire to be near Sasuke, she starts to admit it to him but then denies it.
I don't get into the whole moral outrage thing about Karin's depravity or bad choices, or that Kishimoto has made her a pathetic creature or whatever. As far as I'm concerned her actions and feelings make perfect sense based on her characterization, traits, and history. I think Kishimoto was just trying to reinforce that she's still hot for Sasuke regardless of what's happened, and as you said, used the Suigetsu Comedy Hour to do it.
Maybe it was poor taste, but again, it doesn't bother me or seem out of character for the weirdness of these people. That was kind of the point. That they are weird and abnormal misfits, followers of a guy who set the standard of weirdness and abnormality for the whole story.
As for Karin's denial being the "most cliché reaction in modern entertainment" I don't disagree, but it doesn't bother me. Although Sakura didn't get any specific lines of denial, her tsundere reaction to Naruto saying she was his girlfriend was also cliché, just in a more palatable way. I consider that kind of thing par for the course in a story with such a young target demographic.
If I were Neji, I would be having a cosmic hissy fit over this. I get run through by a spike and I'm totally done for in the few seconds it takes to make an inspiring speech. Sakura (based on subsqeunt events) doesn't appear that far away. But she doesn't activate her seal or summon a slug to try and save him? If Tsunade can surive being split in two with no lasting damage at least it was worth a shot, right?
I thought Kishimoto covered that by making it clear that Sakura could not summon Katsuyu at that point because she had not yet stored enough chakra. By the time she could Neji was already dead. Maybe if she'd had the ability at the time she could have acted quickly enough to prevent his death, but once he was dead that was it.
But because of that power boost she is able to have the energy to not only summon Katsuyu despiste massive bleading (and avoid going into shock), but keep her active to avoid dying until she is found by just the right person who can perform just the surgery she needs. And he's equiped with regenerative healer no less!. Oh yeah, she has enough enery to save everone else too and stand with apparently no ill effects from having split in too.
I don't disagree that it was contrived. I had a very strong, "Hold it... that's it? Everything's fine now?" reaction to Tsunade's quick recovery, especially after such graphic trauma. I mean, I really thought that, for once, Kishimoto would let a character die. But like you said, that's really not his style.
I can't defend Kishimoto's expectation that readers will suspend their disbelief so far, except to say that it's something he has done before. I guess I just don't let it shock or bother me to the point that I can't continue to enjoy the relationships and main points of the story.
When I took a step back and looked at it, I felt that the situation was contrived -- for Orochimaru to be the one to show up and heal her -- specifically so that he and Tsunade could have the conversation they had. As I said in my first post, it was inserted in the story at the point where the parallel between the Sannin and Team 7 is being stressed, and the members of Team 7 have to either make or break it with their decisions.
Everything after the Team Oro nonsense was pretty good, and unless the entire Kakashi/Obito confrontation is going to be talk no jutsu, I am not ready to count Kakashi as dead yet. Besides, he needs his chance to cheat death in a spectacularly fortuitous way like Tsunade just did.
You sound so bitter, Nate.
And didn't Kakashi cheat death in a spectacularly fortuitous way already -- via the mass resurrection you loved so much?
I can't count Kakashi as dead yet either, mainly because I really don't want to. He's one of my favorite characters.