Hmm I dont think hes the hardest hitter, people seem to believe that because he used to be a heavyweight, he still has all that power. He himself has said that he isnt that strong, he just has explosive power.
Diaz is 22, he has great jiu jitsu and his striking is really good too. Did you watch his fight against Sanchez? Wow, great display of ground game and jiu jitsu.
Diaz definitely has more potential in my eyes and if there is a tournament, he should definitely be a contender.