I don’t like the idea of rolling 3 lines
I think the idea is you roll three lines until it doesn't work, then you load up.
People get hung up on the "lines" but you can sub in a guy situationally, for example if their 4th line ices it after a long shift, throw out Tkachuk-Stu-Giroux, or going into the third if your having trouble creating offense, load up a top 6 and shorten the bench.
Personally, I like to have flexibility in our lines, and I like being able roll out wave after wave, especially if we don't have a true shutdown line.