I don't think the anime has made clear how powerful or weak Konan really is yet. She could be really powerful... her back and forth with Jiraya lasted like, a second.
I guess Hidan really seemed to me one of the weakest. Other than the "immortality" thing, he didn't have any great strategy, was dumb as a stick, and underestimated his opponents.
He also relied on combo attacks too much, I got the sene that without his partner he would not have gotten very far.
As an aside, I thought it was hilarious when Kakuzu said to Shikamaru "you are intelligent, unlike my partner." Hidan was like "yeah, you tell him... What??"
