How do you know Karin can no longer use her chains unless Sasuke is dying somewhere? That was simply the prerequisite to unlocking her chains, kind of like how one unlocks the MS, they can still use it afterwards even after the tragic event. Anyway in a VS thread we take the characters as they were at their strongest in their alive state so Karin was strongest when she used her chains.Sakura and Hinata take this rather easily.
Ino is support, Tenten can not compete much and Karin is a support unless Sasuke is dying somewhere.