Karlsson played over 3 minutes a game on the PP, finished the year with 5 goals and 26 points.
Schenn did not play on the PP at all and got 3 minutes less of ice time per game (including 2 minutes on the PK) but managed 5 goals and 17 points.
The Sens clearly couldn't rely on Karlsson like they did last year so they signed Gonchar. He made too many mental errors, was nonexistent in his own zone, his passing wasn't as good as it needed to be, and he got out muscled too often. All of which are strengths in Schenn's game.
Schenn doesn't have Karlsson's exceptional skating or shot. But he's better in every other category, hockey sense, positioning, physical play, breaking up plays, etc..
A closer poll for Karlsson would be vs Gunnarsson.
This isn't even close to being true.
-For 2/3rd of the season Karlsson saw next to no PP time. Chalk it up to being inexperienced as a rookie. Late in the year, he was the go-to guy on the PP and produced very well in that role.
-The acquisition of Gonchar was to bring in a shift in the style of play for the team. We used to be a very defensive, immobile club. Last season we had Carkner, Sutton, and Volchenkov who were terrible with moving the puck and passing. Karlsson got stuck with Sutton who was a huge liability because of his immobility. 95% of the breakouts on that pairing were handled entirely by Karlsson. We're also likely to add Cowen to the lineup very soon, so swapping Volchenkov for Gonchar is going to give us more balance at the end of the day.
-Karlsson had just about as good a rookie year as you could reasonably expect from someone his age, and that includes his playoff performance. He was slow to start and struggled, but by the end of the year he was consistently one of our best defensemen. I think the fact that Clouston played him in huge gamebreaking situations proves that (7.7 seconds to go by a goal down, 3-on-3 in OT, as well as HUGE minutes in triple OT in the playoffs).
-It should also be noted that without the puck he's pretty serviceable defensively. He's a little bit undersized, but still growing by many people's account, but that doesn't mean that he plays a small game. He can out muscle reasonably sized players, and he's also very good with his pokecheck and can strip Star players of the puck consistently. The only area where he gets in trouble is making a risky play to generate offense, but he's getting better at cutting down on the plays that go bad.