Its cute you call it a checking line.
Toews and Makar are not physical defenders. They can handle it fine, but they are not going to clear the net or win battles with their physicality. Manson is physical. G is underrated in this area, he plays the body a good amount and battles. He's not 'good' at it, but he tries. The Malinski/Brannstrom/Kylington group are all very soft. CDH plays way smaller than his frame would suggest. He's very soft... one of the reasons he never stuck as a top 4 guy anywhere post-Isles is teams hated his lack of physicality.
As we look at our defense... we are starting at G being our 2nd most physical defender. That's incredibly soft. I'd argue it is the softest in the league. They doesn't mean they are bad, but they have a very clear weakness teams will try to exploit.