First off as far as value is concerned Brown is not the difference between the 2.
As for Couts best case scenario for the Leafs is that he gets pushed back to a 3C. We already have that in Kadri and the bump in defense is not enough to be looking to add to take care of our 3C position. Brown could be a top 6 winger in less than 2 years. So in essence this trades is a 2nd line winger and a 3rd line center for a 3rd line center. Don't see how that makes any sense for Toronto.
Okay we can move past this 3rd line center nonsense.
1) Couturier is an exceptional defensive forward, maybe the best I've seen in a Flyers uniform.
2) He has plenty of offensive upside and already scoring at a 50point pace. He showed a big improvement before getting injured last year (first time since being in the NHL). Played the 2nd powerplay unit that could not survive without him there.
3) He is a clear #2 center on the Flyers and that's behind Claude Giroux, which is better (right now) than any player in your lineup, Matthews included. Quite frankly Kadri won't get you Couturier and if he did, he would be #2 on your team by line mate quality, not minutes played. because you can put him with anyone in the league and he will make sure they don't look bad. Also remember that the leafs are nowhere near playoff bound and the Flyers are poised to be a dark horse next year. So quality of depth is clearly a case here.
I remember leafs fans saying that B.Schenn wasn't worth a bag of pucks and now not many would rate Kadri over B.Schenn, especially since B.Schenn looked excellent 2nd half of last season. No one outside of Toronto at least. I like Kadri, I would want him on my team. He's a highly skilled player with a top 6 role. But quite frankly to think that an Elite defensive center is not worth a #2 center on a bad team is laughable. I'm not here to **** on your players, because I really like a lot of your prospects and young players. I see a bright future for the Leafs. However, don't get ahead of yourself and start insulting talented players to compensate.
I read a lot of comments on here about Couturiers game and honestly you guys should probably do a little more research before making statements about a player you know very little about. I wouldn't be surprised if Couturier is the talk of the town this upcoming season. He's already a David Backes type and I can see him being Bergeron type within the next 12-24 months.