If the Leafs were a rebuilding/retooling team, id expect a return similar to ROR to BUF. Top 40ish pick (BUF knew they had the 31st pick in the draft at the time of the trade), good/young up and coming Dman (Zadorov) and another promising prospect (which Compher was at the time). Probably a bit higher quality of pieces since Nylander is younger and has a bit more potential upward trajectory compared to ROR when he was dealt at aged 24.
However, the Leafs are a 'win now' team and probably wants a player that helps them immediately. I dont futures are as appealing to them atm
This deal probably falls more in-line with a "futures" package. A reclamation projection and a D prospect (albeit a good one). Id think they want someone more established