as an offensive player, you can measure your size by your hammer size.
as defender its much more complicated, because def units die along the way and so on. So there is no actual way to calculate who cooks more defensive units in a server.
Is it possible to add some trained units counter in some personal statistics page? I dont think it would be too complicated, but as defensive player it would allow players to measure who cooked more def units.
Secret society was another option, but its buggy as hell as "Troops died defending" are always not adding correctly , so the amount gets lost .