As abstractapplic noticed, there are three elemental groups of six champions (earth, fire, and water) plus the nightmare, and mixed team comps do much better than something like 5x fire. My guess is that the group of strongest individual champions just happens to be fairly balanced between the elemental groups and that the elemental advantages aren’t strong enough to make a big difference vs just picking the strongest champions (I hadn’t even noticed the elemental groups when I picked my teams, and I still picked a balanced team with basically the same comp as everyone else).
As abstractapplic noticed, there are three elemental groups of six champions (earth, fire, and water) plus the nightmare, and mixed team comps do much better than something like 5x fire. My guess is that the group of strongest individual champions just happens to be fairly balanced between the elemental groups and that the elemental advantages aren’t strong enough to make a big difference vs just picking the strongest champions (I hadn’t even noticed the elemental groups when I picked my teams, and I still picked a balanced team with basically the same comp as everyone else).