She's not an auto win at all; though she does heavy damage, she is easily overpowered as well, and lacks necessary immunity and her standard fails against dodge, which cripples her when you can't reset her mystery. I play Kon*l the time, and I can't tell you how many times Shisui/Madara/AnbuItachi teams shred me, same with minato/5kagemadara mixes. There is no perfect team, like Hiruzen only works if you have much higher power or if they don't have an itachi edo tensei, which makes Hiruzen a top favorite for high power p2w individuals in sage for quick battles.

Don't stress it, we'll all be crying once Kakuzu Earth Grudge's skill books come out, then naruto online becomes Kakuzu Online