Gai - Meh. He's been dying since day one. Anyone who has a capability that might cost him his life is doomed to die from it during the course of the story. The real suspense is not if he uses it and succeeds, but if he survives from it. (And by succeed, I mean that he will successfully weaken Madara enough that Naruto or the ad hoc Team Minato can finish him off.)
Kabuto - Surprise factor: 0. Skeeve factor: 10. Welcome back, weirdo.
Not Team 7 - I think Kishimoto is way more attached to this team than his audience is. They're all backstabbers in some way or another. None trusts the other ones, so it's hard as a reader, to get behind them. Kishimoto clearly likes them and keeps pushing them into the story. But the team stuff is so lacking. I think I would have liked them more if Kishi had recast them as Akatsuki-like villains (monsters each in their own right, and only staying together because it served them), rather than this lukewarm "I-don't-have-anywhere-else-to-go" psuedo-team thing. I mean Juugo was terrifying when we first met him. Couldn't control himself in a jail cell. Now he's on a flippin' battlefield — shouldn't he be freaking out right now?
Karin - Whatever bond or Karin/Sasuke shipping Kishimoto hinted at in the last few chapters is finished now. Karin is at a complete distance from Sasuke, no closer than any of the other Not Team 7 members, and she's being her normal Karin self about Kabuto's return. She's totally lost focus on Sasuke. Parallel this to Sakura-Naruto, and Sakura would not have jumped back, lost focus and be loud-mouthing about a new-comer. She'd be focused on Naruto, and demanding everyone else's silence and attention until he was showing signs of true recovery. If Kishi wished to further develop her role as a future companion for Sasuke, having her mature and recognize true love after having almost lost it, then that opportunity is quickly closing.
Oh yeah - I knew that scene back at the bridge was fishy! Kabuto was collecting dna from Sakura's four-tails wound, not just healing her so they could beat Akatsuki, like he said. So file him away as another one with some tangible kyuubi connection, whether anything comes of it or not.
@tricksie About team taku kishi mentioned about the company seisuha ordered him to write more about team taku because they liked the team more than kishi does.