Very good game by EK against NSH. It was the first mistake free game I've seen since watching the last four. As always, his passing and transition was excellent. He wasn't as aggressive in the d-zone as in past games, but he was able to stop the NSH attack, retrieve the puck, and minimize chances against.
Play style, he is not playing like classic EK. Very little jumping into the rush or roving in the ozone. He looks like more of a fit in San Jose the way he is playing right now which is a lot more conservative.
It was the style David Cameron wanted him to play in Ottawa. Far less skating rushes, stay back more, not much pinching unless he's already in the offensive zone, or it's turbo mode (getting into the playoffs, or being in the playoffs). Stay back, deliver, react, get the puck back, get it the right way. I think Cameron taught him a different style of his own repertoire. I mean, listen to the coach and the players when Karlsson played at the top in that system:
I mean, sure, he's not that strong battling muscle monsters. He has some problems to pivot after getting his achilles tendons (fitting for a God, right, lol) cut off by scrub Cooke, getting half his heel removed... but still, he reads the play really well, he blocks shots, he steals pucks at a top level and pushes the play up the ice with world class quality. You don't have Karlsson to wrestle around your own net, you put him on the ice to be most assured the pucks are being fired against the opposing net. He's very solid, in game shape in his defensive zone, but that's not the intention of his team role.
Both his teammates - and his coach - in Ottawa meant he was just as good defensively as offensively, playing and coaching with him every day. Now, that was before he removed half of his heel, lost his child and whatnot ridiculous, grevious incidence that didn't happen during that season for him. So, he was backstabbed by the franchise, as he saw it and traded from what he considered his home, to San Jose. He saw it as his home. Mentally, for most people, such a rough year would take time to heal, individually, to be able to accept all of that. As for individually driven persons as NHL pros with a big ego, oh man. They're in for a ride. Some have the humility left, some don't. Karlsson has humility, don't worry.
Long story short, I don't even know why you worry that much. Karlsson has had a mental nightmare ride. So many tough recoveries and sorrows. He can still play the game at ridiculous level, he just has to smelt all the crap, the crap fan has thrown in his general direction. When he's done with that, you have a ridiculous player on your team. He's only playing as a shadow of himself right now, but he'll get there, when he's ready and somewhat understands his teammates - and vice versa.
He spoke of "years" to learn what it is to be a San Jose Sharks player. I think he really meant that, in his thinking of playing hockey. Not until he plays years with San Jose, will he know the players good enough to be able to work with them properly, which was what I think he tried to describe. He knew the guys inside out and they knew him in Ottawa. Then you can create magic.
You want some stats? He's tied 2nd in the league in takeaways (Barkov leads with 27, Marner has 25, both are centers, Karlsson is not). He only has 13 giveaways, that's low considering his style of play. His save goalie percentage on ice the is .855, which is really unlucky considering the goals scored against him on replays, compared to other defensemen on San Jose allowing similar situations. His corsi? Really good.
End story of it all? You want roaming Karlsson. He's much more fun to watch, or change the setup considering to the game, if DeBoer was smart enough. Or, you might get him at crunch time regardless of DeBoer, because he wants to win.
TL;DR: He'll get there if you have the patience. His problems are mental, I would certainly assume.
edit: So I might've mixed the coaches in Ottawa. I don't care.