Unless Kishimoto makes a bunch of throwaway villains, I can see the final five Akatsuki taking on three or more of the Konoha nin at once.
If Kisame 30% can give the entire team Gai a run, surely the full thing must be monstrous.
Itachi I guess is reserved for Sasuke, through I really don't see him beating his brother by himself. If Itachi is as uber as he's been shown, Sasuke shouldn't even be able to touch him, let alone defeat him in a swirly-eyes showdown.
Bluehair, knowing the general scheme of Naruto, is probably so androgenous he makes Deidra look like Sylvester Stallone. If I'm wrong and she does turn out to be a woman, she'll fight Sakura, Karin, or every female character in Naruto at the same time.
To make me happy, Zetsu needs to bite, or at least attempt to bite, three nin with his head-snappy. That thing just begs to be used, and the fact that he can meld with trees and appear underground just makes its use so much more logical.
AL better be UNGODLY strong. This is a guy who shouldn't be beat by protaganist-rage Kyuubi, Swirly-eyes, or a combination of the two. AL needs to be uber, not to give Akatsuki credibility, but just to make it seem like, hey this group actually could take down an entire village on their own.
Kabuto…I really don't see getting too much attention. But that's more hope than reality.