Yes I get that with the size difference but at heavyweight you need technique along with punching power. Remember Butterbean as he was useless and was bigger or twice as bigger than many of his opponents and he was out boxed. There speed and technique overcame size. In rugby size matters depending on the position you play as trust me I have come up against guys when I deemed it unfair but saying that would have the edge in certain areas they wouldn't. Reach is a big thing in boxing plus being able to have a knockout punch. If you are smaller and shorter like a Tyson then you have to get in on the inside but if you don't have a punch like many of the boxers don't have around today you are screwed. Joshua is a prime example as has everything size, power but he has a glass jaw and everyone knows that now. Size and power are obviously an advantage and yes make a huge difference and should overcome smaller boxers if they have the skill sets.