The players need to learn how to play as a team, whether creating offence and stopping a rush, and their designated roles/positioning on ice. Learn to play successful 2-way hockey that starts with being accountable for your checks. Tkachuk may have had some success on the breakaway on the counter by waiting at the blue line, but it has also resulted in scoring opportunities/goals the other way. Stutzle keeps making the same mistakes every game when he holds on to the puck too long, some of it related to players poor positioning on ice to receive a pass.
These are fixable mistakes. Despite knowing what ails them, they were consistent at making the same mistakes over and over, which goes back into the question of accountability.
The players need to hold themselves/each other accountable at all times. That's how great teams are built.