When you see that Ryan White has more goals in the last 3 years than Riley Nash you might realize that they're not the best way to evaluate 4th line forwards (or anyone else). Nevermind that Kuraly has only played 10 games in the league.They can? Because their 5 career combined goals in almost 70 NHL games says otherwise.
If anything, it's Nash, as much as I dislike watching him play, who can "play the game".
I don't even have an issue with Kuraly as the physical guy/PKer on a 3rd line with a couple of point producers, even if one of those two producers is Backes.
I just have an issue with the ancient notion that the 4th has to be 3 guys who play hard but can't put the puck in ocean, or worse yet, generate anything resembling quality scoring chances. Two of these types is plenty.
Offensive players are not going to succeed in a 4th line role with limited and inconsistent ES minutes with guys who don't compliment them offensively. The best thing your 4th line can do for you is take SH minutes off your top players so they can play more at even strength. Beyond that, being physical in their ES shifts isn't the only way they can contribute, but it's easier, and it's an easier way to make your team more physical if that's what you want.
You have Kuraly, Acciari, Nash, Schaller, now maybe White. If any of them are in your top 9 more than temporarily, that's a problem. When they won't get unproductive guys like Beleskey and Spooner out of the top 9, that's a problem too. That's where you're taking away real opportunities for skill players. Unless you're a Marchand and bring lots of other things besides offense, the 4th line isn't the place for you to succeed.
People fall in love with the idea of a "kid line" but it's backwards thinking to shift SH minutes on to your top ES players and shift minutes in offensive situations to your 4th line.