I'm not being snitty so don't go there, I don't see where Laine fits into the Leafs system, the top two centres are goal scorer's and not set-up men and Laine needs a set man to put the puck on the tee
Matthews being a lefty is more prone to passing to the RW, it's the same with Tavares. The LW on both lines are hard skating forecheckers, Laine's biggest deficiency is his skating, he has average edges and speed, he is big and strong no doubt, but he's not a "work the boards and corner" winger.
He might work with Kadri, but Kadri is the match-up guy and Laine is a pure offensive threat, because of that he doesn't compliment the line, both wingers on the line have to support the centre when he's in deep, which means the wingers generally play high and have to get back first.
Either way Laine to Toronto just doesn't work he'd still get his 40 probably, but the cost going back and the money he'll want just doesn't fit the Leafs next 5 years