Sure, but that's not predicting the future to a high degree of certainty. People predict how others will react all the time. The most convincing humans are already very good at it, so we know it's possible to some degree. While I agree chaos theory puts an upper limit on how well someone can predict the future, there's no particular evidence that human ability is close to the limit.

I think you're imagining some mastermind that has to get everything right or it dies, instead of a master politician or businessperson who's a few percentage points better than the existing competition and for whom the advantage compounds. Yes, Less Wrong is way too hysterical about everything, but charisma that's better than human is a problem.