How many of those 2nd rounders make it to the AHL? I'm not talking about making it to the NHL. That is just down to a numbers game and how well you can develop them. If they consitently develop at a reasonable clip and still can not make it, I do not even count that as a loss. For example, if Timashov ends up not making it, I would not call him a bad pick or even blame the development team.
In 2015, 9 out of 15 players (excluding Korostelev and Desrocher) drafted out of the CHL after Desrocher at least made it to the AHL with the team that drafted them (i.e. their rights did not expire). 7 out of 14 after Mattinen in the 2016 draft. 54% between those drafts is not an amazing number, and obviously most (if not all) of them will probably not even make it to the NHL or even become great AHL players, but at least they made it there. Leafs went 0/3 with one having an asterisk due to injury (Korostelev).
In my books, if you are drafted out of the CHL and do not at least make it to the AHL, it was a bad pick unless there is a really unfortunate circumstance like an injury that totally killed them. Of course, as you get to earlier rounds, those expectations get higher.
Hitting on a top 5 pick and also doing well on Dermott in the 2015 draft is nice work, but it is pretty average considering the amount of praise Hunter/Hofford received for being some elite scout and the number of picks he totally whiffed on as well. I would expect most scouts who can not do something similar to that end up fired eventually. Dubas should and can do better than at least Hofford in that region if we are going based on his Leafs track record to date.