My profession is college teacher, but my vocation is freelance game designer, and I've had half a dozen board games published (strategy games, not family games). While I'm not planning to design a hockey game, I tend to think like a game designer when I hear all the discussions about line combinations. And my questions are, does it make a difference and how does it make a difference who is on whose line?
I'm rather skeptical that line combinations matter at all in the short run, or matter much in the long run. But if they do, there must be reasons why they do. So in game terms I can change my questions to be these:
What are the various purposes for putting people in a particular line? Scoring line, checking line, is there more than that, other variations of that, other combinations? Are there lines, like the fourth line, that are there just to "hold the fort" and not let the score change? I remember when New Jersey's fourth line was their checking line and went up against the best line of the other team, but that's never been the case at Carolina. When Carolina won the cup, we rolled three or four lines and just came at the opposition in waves and wore them down. Is "energy line" one of the possible ways to construct a line?
What are the characteristics of players that come into consideration when you put together line combinations? Some players are good at retrieving the puck along the boards--grinders? Some players are good scoring. Some players are good at passing. Some forwards are particularly good in defense. Do you want a line with a scorer, a grinder, and a defender, for example? Would "hard worker" or "hustler" (energy player) be a characteristic to consider? Do some lines require better face-off men than others, and even a good secondary face-off man?
In other words, if you are going to make a list of characteristics and rate each player and use those characteristics when you are deciding who to put on the line, what would those characteristics be?