rivals big trade

I feel like Marner has become underrated these days. He's still a good winger who can put up close to 100 pts over 82 GP, and is probably a top 5 RW in the league. However, I saw a trade that said Laf and K'Andre for Marner and Niemela is a bad trade - I don't get it. So here's my package for the Leafs.
David Savard provides a defensive right shot defenseman that the Leafs need.
Jordan Harris is a young 3rd pair LD who makes more sense as an option on the 3rd pair over Timmins.
Jake Evans is swapped for David Kampf - Kampf is worse than Evans and on a worse deal, so this is net positive value for MTL.
It seems unlikely that the Leafs will be able to keep Max Domi, so they also acquire a young, cost controlled 3/4C who might have 2nd line upside as a Danault-type player.
They also get two first round picks as well as Emil Heineman, who has upside as a middle six F.