Other than Itachi, Pain & Tobi (if you count him), I would like to argue that Kakazu is the strongest member of Akatsuki. Kisame, Sasori and Konan may be powerful but none have the huge assortment of powers and experience that Kakazu does. Iron skin, all of the elements and over 100 years of experience, many people seem to underestimate Kakazu. Nobody really posed that much of a threat in the big fight they had and not even Kakashi showed any strong signs of being able to take him out.
Then why did he get plot no jutsu'd by Kishimoto if he's soooo importantly strong?
Kishimoto likes to showcase jutsu, he'll use whatever he has around to demonstrate how powerful this 'new technique' is. Take Kabuto for example. In normal conditions, there is no way a Kakashi level ninja like Kabuto would've been so point-blank hit by a rasengan but because of the surroundings and plot no jutsu, who else was he going to use rasengan on? Not Orochimaru or Tonton that's for sure. The same is with this fight, Hidan was underground and that leaves Kakazu. Kishimoto got bored of his new playtoy and randomly killed Kakazu off, which was unfair to the character. Plus there's the fact that Kakazu may never have been defeated if he hadn't been taken down there, another opportunity with an equally as powerful ninja (Kakashi, Killer Bee, Orochimaru) may not have come up again.
Do you agree/disagree? Discuss. It just struck me today how hugely strong Kakazu's strength is even up with the huge power levels of the ninjas in the series lately. Kakazu was a boss, and needs to be ranked higher in lists in my opinion.