As a Leafs fan who understands farm systems in general and how highly touted the Jays system is, I was scared at first at this trade. But then I realized that this is not the Maple Leafs, who I would never condone making a trade like this.
This is the Toronto Blue Jays, who just made one of the best trades I've ever seen, and who are much closer to being a contender than the Leafs have in recent memory. Sure giving up 2 top prospects is scary since we as fans read up so much on these guys, but as others have mentioned, this is the only knuckle ball pitcher in the league, the only knuckle ball pitcher to win a Cy Young (which happened to be last season), and he is not a 'one season wonder'. I think having a knuckle ball pitcher, especially a veteran, can only help the other pitchers in the rotation hit their potential. Additionally, he is known for pitching many complete games, so the Jays bullpen can hopefully have more rest with him in the mix.
If this trade sacrifices some future (2 top prospects in a system with many other hopefuls) to put the starting rotation over the edge so this team can win games NOW, AA has my full support. He can still make more deals after this.