I have noticed interesting trends in the strategies of both Zoroark and Ditto. Both Pokemon rely on the ability to be something that they are not, and confuse the opponent. However, because both ruses are easily broken, I do not think that either will create too many disturbances in the trends of the game.
However, Sun-Tsu commented on how Surprise can be a very effective tactic. Being in UU or NU does not invalidate the power of either Pokemon in the OU tier as a surprise tactic.