Turris being a 3rd year NHL player is great and all, but he has been a pro-player for 3 years...he has 130-ish games because he wasn't good enough for the NHL on what has been some piss-poor rosters in Phoenix. They have been trying to hand him an NHL job and really haven't been able to. So, yes, he has experience, but he isn't established as a proven NHL player whereas Kadri was always going to be starting in the AHL last year, and forced his way onto the team with his play/poor play from others. I'm not exactly sure how that implies that Turris is better (not that he doesn't have a high ceiling) but when you are trading prospects you need to be sure that you are dealing from a strength for a weakness, or are dealing a safer player for a high risk/reward guy. I'm not sure how Turris falls into either category as the Leafs aren't particularly deep with top 6 prospects that are going to reliably be NHLers.
Frattin cleaned up his act last year but could destroy his career like he was doing in College. McKegg is a guy with some production who isn't exactly a prototypical NHL prospect. And guys like D'Amigo/Ross/Biggs are either several years away or project more in the 2/3 kind of role rather than 1/2. Colborne might be top 6 too but also has to show for a stretch longer than 20 games that he can score like one. There are some good prospects in the Leafs system, but because Burke was dealing away 1st rounders for Kessel, they are 2nd/3rd/4th round picks. Those picks can be good, but they almost always come with a warning label, or take longer to develop. The Leafs don't have the kind of prospect pool to be dealing away guys with some high potential...and to be honest, I really like the pedigree of players that come out of the Knights system. They don't all end up as stars, but they have produced enough NHLers who have had reasonable success in the past while that I'd like to hang on to the guy who came from there. Kadri was carrying some brutal teams to the postseason with his play.