yea, lets cry about Rin being OP like there is no other OP support in game... maybe BT Kabuto and Taka Karin? both are freaking annoying.

Rin´s passive 1 (the mystery damage reduction) can be fairly easily countered... either by using other mystery, by using heavy standard attack based team or by using heavy damage chase teams.
Rin´s passive 2 (chases cannot kill your team for 3 rounds) is partly negleting the usage of heavy damage chase team as a counter to Rin... however only to a certain extend. If at least 1 of your chases causes either ignition or poison... she can die in the end of the round and you have full damage mystery next round...
She is strong, but since she is not immune to debuffs... she is not a godlike ninja... not in our power level... Maybe at 2-3M BP, she is beast, but under 1M, she is just annoying.