Check Thornton’s GF/GA against Pittsburgh and specifically against Crosby/Malkin and then compare those numbers to Karlsson’s a year later. Thornton in the finals was literally the reason we lost, and he was what, 4th on his own team in scoring in those playoffs? Meanwhile, Karlsson led his team in scoring and had a higher PPG than Thornton as a defenseman carrying a team whose best other player in those playoffs was Bobby Ryan. If the Senators won the Cup in 2016-2017, Karlsson’s run would be talked about as a GOAT playoff performance. I love Burns and Thornton and I agree Burns’ 2016 playoff performance was incredible but there is not a single player in the NHL except for maybe 2009 Evgeni Malkin who boasts a playoff run that is comparable to Karlsson’s in 2016-2017.
Karlsson has been voted best at his position twice and 2nd best at his position twice and in the seasons he hasn’t been up there, it has almost always been due to injury. He also deserved to be voted best at his position in 2015-2016. Thornton meanwhile in his Sharks tenure has been voted best at his position once and has been voted 2nd best twice. That’s one more season in a shorter time frame that Karlsson was voted best in the NHL at his position and he would have easily been voted best at his position if not for his injury in 2013 and you can probably say the same for 2018 honestly. Karlsson has led defensemen in scoring like 5 times and Thornton has led centers in scoring once.
When you compare the performances of each player in key moments, such as the playoffs and international play, the gap is severely widened. Karlsson’s Olympic performance in 2014 and his playoff performance in 2017 are far, far ahead of anything that Thornton has ever done outside of regular season NHL hockey. Given that, I think it’s pretty easy to deem Erik Karlsson superior to Joe Thornton.