Size only matters up to a certain point. At 175-180 or so, you get into the territory where size begins to matter less and this is especially so at 200 lbs and above. This is why many would pick say Walcott to beat Lyle. And we don't have to imagine too hard because the 220 lbs Lyle was actually beaten IRL by a Walcott sized fighter in the person of Jerry Quarry. We see with punching power, a guy like say Bob Satterfield who hit harder than say Muhammad Ali. Even though Satterfield was 175-185 pounds and Ali 210-215. In fact, the relatively diminutive 5'11 200-205 lbs Joe Frazier hit harder than than the 6'5 250-260 pound Buster Mathis. And stopped him as well. Of course, weight matters the lower you go. So even a devastating featherweight puncher won't hit harder than a relatively light punching light heavyweight. Just like a 115 pound ATG fighter likely wouldn't beat a mediocre 210 lbs heavyweight. But a 185 pound ATG fighter like say Ezzard Charles could box rings around a mediocre 210 pounder. Even though they are both smaller than the 210 pounder, at 185 lbs, the smaller man is big enough where other things can make up for size and big enough where he can hypothetically hurt the larger man. Also, a washed up antique, belonged in an ancient history museum 215 pound Evander Holyfield beat 310 lbs Valuev who was in his prime. Well arguably anyway. The point is, smaller fighters of 175 and up can hypothetically beat larger men, depending on the individual fighter.