"Conversely however, the user's original body is left defenceless while this technique is active, leaving it susceptible to attack until they return. The mind transfer moves slowly in a straight direction and takes some time to return to the user's body if it misses. Similarly, if the opponent's will is strong enough, they can force the user from their body, as Sakura Haruno did to Ino Yamanaka during the Chūnin Exams. Also, if the user's chakra level is low, the technique will be harder to maintain. Furthermore, should any physical injury befall the victim's body while the mind-link is active, it would cause the user's body to also receive those same injuries. This can be rectified if user cancels the technique before the victim's body receives the damage."
I have to say Mikoto because even though she was a jounin level kunoichi she hasn't fought in ages thus her skills would be dulled to at least that of a low-chunin. Rin because she was only ever mid to high-chunin and she was medic ninja and didn't have much skill than what was required for chunin in Taijutsu or Ninjutsu.