Even score-wise, I think their round robin match at the World Tour Finals in 2011 was the better match. Although Nadal wasn't doing great, Federer was, and that showed in the score.
As far as giving Nadal a taste of his own medicine - I think Federer eventually realized it's not a cheap tactic if your opponent does the same thing.
I am an unpredictable player. Even I surprise myself with some of the shots I make.