@TheDog  
I do not really like the character, but I feel Hidan is being grossly underestimated here, the mistake all of his victims made. Shikamaru may have dodged Hidan once, but Hidan assumed he had Shikamaru more-or-less trapped and Shikamaru had been planning, preparing and psyching himself up for that dodge (not to mention that it was a plot-critical dodge, and those always succeed). Also, it is more like the old Shikamaru not to spend any time getting stronger, but as Shikamaru now has taken on more “troublesome” responsibilities, it is likely that some of those come with the responsibility of training. We see his jutsus improve, too. Speed is not really Hidan’s strength, though. I would say it is his relentlessness and trickiness. He just needs one drop of blood, which being invincible gives him lots of chances for, and ends up killing people a lot stronger than him (which we just get hints of, like that Jinchūriki) through use of his ability. He was also probably awesome for Kakuzu to tag-team: do not worry about hitting him, just get a drop of any enemy’s blood and cover him to guarantee a kill.
 
Hidan’s greatest weakness is his brain, as he was easily tricked multiple times and does not truly utilize his ability: catch blood, go hide, do ritual. The writers probably had Hidan kill Asuma and paired him up against Shikamaru because he is a dumb enemy whose ability needs to be “figured out.” Shikamaru did have to have some Batman-level preparation to use and kill Hidan, as well: a Kakuzu blood vial, a forest booby trapped with tons of explosive notes, a hidden huge-ass hole that opens with a trip-switch in a clan-specific sanctuary area that has almost deus-ex-machina special rules. Also, by the rules of the show: he is still not dead.

@TheDog  
Eh, got me there.

@Turbotowns
 
Yes. Has one move that requires set-up, and is slow enough that his attacks can be dodged by Shikamaru, a guy who refuses to actually work on getting physically stronger.

@Turbotowns  
It’s not that Hidan is weak, it’s just that the other members are stronger. Except white Zetsu, for he is fodder. (And probably Karin if you count taka.)

@TheDog  
You consider Hidan-THE IMMORTAL-weakest akatsuki?!?

Pinkie is weakest Akatsuki and Twilight is most broken Gary Stu Akatsuki.

@Roy-of-Asturia
 
I can see Dash as Kisame. I can also imagine Pinkie making several sacrifices to Jashin

@Roy-of-Asturia  
Another prediction:  
Mare Do Well -> Tobi

Rainbow Dash -> either Kakuzu or Hoshigaki Kisame  
Fluttershy -> Zetsu
 
Sunset Shimmer -> Pain