To the question of whether a player benefits from playing with better players, of course. If Karlsson and Barrie switched teams this season their numbers wouldn't be the same as they currently are. Karl in his prime dominated with no superstar forward, but I'd say Hoffman, Stone, Ryan, and Turris suited his skillset more and Ottawa played a far superior passing game than these Sharks. The lack of talent up front is part of the reason his numbers are low but I think Boughner's system plays more of a role. Karlsson is still a gifted passer, he still knows what he's doing in the offensive zone, how to find open guys and generate scoring chances. After watching this team for four months it feels like the D don't play a great role in the offense beyond making breakout passes and getting shots toward goal (or attempting to). It's behind the goal-line oriented, with the "pucks in deep" and relying on the forwards to win it back to create a cycle. There's hardly any rush offense that they don't find accidentally. We've seen many times Karl join the rush and he doesn't get the pass. Or when he does, and it ends up in nothing because there's no available pass.
With more luck with posts and missed grade A chances Erik could have 29 points instead of 19. It's mind-boggling that last season, where he wasn't that great offensively, he put up .61 assists per game and this season it's less than 1 in 3 - and I don't think he's been any worse offensively this season. I think he's doing more things he wasn't doing last year. At least in the last two months this season he's scoring at the pace he did in his prime. I have a hard time believing he won't have something like 12-40-52 next season because surely there has to be some regression to the norm.