Well define what 'toughness' even means and then show me some real data on how it helps teams (in the context of the top 6). I'm wide open to being convinced.
Toughness as described not with fighting per say--but going in the tough areas such as the corners and standing in front of the net or tossing legal hits around to throw the other side off of their game
Look at the Hawks--on paper and theory they are not a tough team--but when you see guys like Toews, Kane, Hossa and others--they are hard to move off that puck and will go into in parts of the ice or stand in front of the net that are core will not do. Kane is 5-11--but he is hard to move off of the puck and he gives and good as he gets--without taking stupid pms
key aspects to toughness as defined by Lord J T Shark overlord of Arkham Asylum
1) hard to move off the puck
2) going to the rough parts of the ice
3) Ability to check without taking penalties
4) Ability to stand in front of the net game in and game out
5) Mentally able to bounce back after a bad shift
6) the other team need to think before they come flying down the wing on your team
7) Play a full game
8) Play both ends of the ice
but those are just 8 off the top of my head