Really? In the last 9 years Pittsburgh is probably the only Champion without a true all-round great Defenseman. On the other hand LA & Boston won Cups without ay forwards who are in the class of the Crosdbys & McDavids - I mean Krejci & Kopitar are excellent centers but do you seriously consider them Hart Trophy or 1st-team AllStar material?
AT the moment I wouldn't trade Mathews or Karlsson straight up primarily because of age and circumstances, not positions - the Leafs without Mathews would be incapable of making the most of having Karlsson on the team - and by the time they get there Karlsson might be used up & injury prone. Mathews career timeline coincides more with that of the franchise.
Well, I did say "it just seems harder to win a Stanley Cup without a number one centre as opposed to a number one defenceman" based upon my observation but I will try to illustrate my point of view with the following:
Kopitar was one of the best centres in the NHL and was considered a true number one centre (he is also paid like one) when the Kings won their two Stanley Cup and awarded him a huge contract extension. Is he a first line all star? No, only because there were other centres that are still better to him. That doesn't mean he wasn't one of the best centres in the league. He was favourably compared to the leagues top centes. He was on the Kings two Stanley Cup teams and averaged a point a game both times. He was also their leader in points during both regular seasons. He was also considered one of the best defensive centres in the NHL. Is he still one of the best now.? Not likely but when the Kings won their Stanley Cups he was.
https://sports.yahoo.com/blogs/nhl-...best-player--it-s-anze-kopitar-144742926.html
In the last 8 Stanley Cups, Pittsburgh with no legitimate number 1 centre defenceman, has won two Stanley Cups with arguably the best centre in the league with Sidney Crosby and Malkin. Chicago has won three Stanley Cups with Toews (and winger Kane) and a strong defence corp which included Keith and Seabrook. Yes it could be said Boston did not have a true number one centre when they won the Stanley Cup but overall offensively and defensively (with Chara on defence) they were a very good team. Crosby and Toews are arguably, considered two of the best players to have played in the NHL (both in the top 50) and in total their teams have won 5 Stanley Cups over the past 8 years. Kopitar led teams have won 2 Stanley Cups.
Without Crosby, Malkin, Toews and Kopitar, do their teams win the Stanley Cup? You never know but my best guess would be no.
Mind you as per the article below, a number one defenceman is also very important requirement for teams winning a Stanley Cup. As noted, Pittburgh is one team that did not have a legitimate #1 defenceman on both their Cup winning teams. The Kings and Blackhawks had Doughty and Keith/Seabrook respectively. Would they have won the Stanley Cup without them. Again who knows. What is common over the past 8 Stanley Cup winners is that 7 of them had a star centre and defenceman on their team. Without one of them, they may have still won the Cup but probably not as both players were vital to their success.
http://www.tsn.ca/ducks-pens-trying-to-win-stanley-cup-without-no-1-defencemen-1.752995
As a Leaf fan, I am just hoping they can have at least 4 top defencemen on their blue line who are truly considered at minimum top 3 quality.