From just the perspective that the Toronto Maple Leafs have lost Gardiner and Kadri, while gaining Kerfoot and Barrie, it doesn’t seem like they have improved a lot.
But they were already pretty good, despite consecutive first round losses to the Boston Bruins (they would have won both if the best team always won).
The new Leafs team is deeper, has the majority of it’s core pieces closer to their peak seasons, and most of all, it has taken Ron Hainsey and Nikita Zaitsev out of the equation, as no other contending team had two worse players in their top four.