Lou was brought in to mentor Dubas. He was a rookie remember with zippo experience. The plan was always to transition. Lou eluded to it when he was brought in. They probably did it the Leafs way and paid him a boatload of money he could not refuse and the position was the GM of the Toronto Maple Leafs after all.
Dubas was considered the next young bright mind of hockey. Colorado wanted him if Lou stayed on. Hence probably why Shanny expedited the transition. Colorado was fortunate they never landed Dubas. Fleeced Dubas instead and acquired Kadri and won a cup with him.
2015 draft Arizona picked Strome 3rd overall. That's Arizona for you. That left Marner and Hanifan. Babcock wanted Hanifan. So Leafs were fortunate in a way to land Marner and fortunate to win the lottery to land Matthews. Also fortunate they didn't listen to Don Cherry and picked Nylander instead of Nick Ritchie. After all this fortune and good drafting mass complaints about the core 4 forwards. Players picked ahead of Nylander ... Bennett, Dal Colle, Virtanen, Haydn Fleury. Interestingly in Nylander's draft year picks 1, 2, and 4 are currently playing in Florida.