Actually calling all the penalties. I see all the time "If the refs called every infraction against McDavid the Oilers would be on the PP 40 minutes a game"
Good. Eventually teams will. learn to play cleaner. Less hooking, slashing, cross checking, and interference will benefit the league's stars and hurt the bottom 6/bottom pair guys who don't have the talent to keep up.
Allowing this anything goes style of hockey majorly works in favor of the gritty less talented, deep teams (Habs, Islanders, and even Vegas to some degree) and hurts the teams with huge portions of their cap dedicated to star players who get their offense stifled in the playoffs