From 03-08 Miguel Cotto had viscous left hook to body, whos new#1 body puncher?

I just wathed 15 or more fights of his from his early days over the last week. he must have had one of if not the best left hook to the body ive ever seen in my life. Granted im only 27 and boxing since I was 14 so I didn't watch much till then but why did he not use that punch vs Margarito in their 1st fight and why have I not seen him do that at all anymore? just makes no sense to me. Who out of all the rising stars today is the hardest body puncher? Id say GGG or Matthysse but they are just hard punchers no matter where they hit u