I'd actually love to see an entire line scrapped from the NHL. This is a way to make the game better. 2 offensive lines and a checking line or 3 offensive lines, and throw the 4th line caliber players away. That means any enforcer / energy guy will actually need to know how to play, no more room for useless goons. That way, you actually see the stars play a lot during a game (which is what you pay to see) and the players always remain happy, since they all see loads of ice time. It's also a good way to stay in the game, since you don't get cold and out of focus because of the long stretches of inactivity on the bench.
That would also allow for a thing the Russians do that I love, because it allows for added chemistry and possibilities, which is always roll the same 5 players at a time. the same 3 forwards always playing with the same 2 Dmen. This is a system I love. It allows for better complementarity (for example, you might want to put a big and tough Dmen at all times with a line of 3 small and skilled finesse forwards, so that nobody takes liberties on them. Might also want your best puck mover at all times playing with your best offensive weapons).
I'd keep 2-3 healthy scratches though (who might be the present regular 4th liners of the league) because you don't want to call up a player everytime there's a minor injury to one of your players, and it's good to have somebody to push you in the back and try to take your spot if you fall asleep.
All that being said, for this to work, I think the schedule would need to be reduced to about 70 games a year, which is also something I'm all for. This is indeed a way to counter the ill effect of a watered down product, but the NHLPA would of course never agree to that.
edit - typo