Weight bullies give the illusion of punching hard. When they fight opponents nearer to their own size, they look pillow fisted. For example, we saw Teofimo Lopez recently, he was catching Claggett clean but had barely any impact. Against Loma he looked like he hit very hard but in reality that was the huge size disparity.
I agree with the concept of weight-bullies and their power being overrated because of this but disagree with Teo as an example. Yes, his power has decreased as he's moved up but everybody's does and he's not really all that big for 140 afaik. Also Claggett was able to take Teo's shots better than, say, Commey or Magdaleno because he's got some pretty tight defence and is tough as old boots with a very sturdy chin. Bam Rodriguez is a better example of the phenomenon you're describing imo.
