The question is not really about who the Leafs drafted or did not draft. That is, as many have said a bit if a crapshoot. As many also have said, we won't know for a couple of years yet how the players w are discussing will turn out. (My preliminary guess is that the Leaf picks will not be the best possible but they both may turn out to be bottom half of a team NHL contributors. But that remains guesswork. )
The real question is about asset management, as at least two people have said. In a draft with a top tier and then thirty or forty very similarly rated players, is trading #30 and #39 to move up to 22 good management? If the draft is aptly described with some gambling metaphor, it is better to have two very slightly worse chances than only one slightly better chance.
There was a TSN study that showed late first rounders become NHL regulars (a 200 game career was the criterion IIRC) at a little over 20% rate. For the sake of argument, say the 22nd pick hits at a 25% rate, pick 30 at 22% and 30 at 20%, it is manifestly better to have the two picks. In fact, the difference is negligible among picks in that range, so the argument for keeping the picks is, if anything, stronger than my hypothetical numbers.
You would have to be very confident that an asset obtainable with the higher pick was significantly undervalued to make the trade worthwhile. Presumably, that is exactly what Burke and company thought about Biggs. It may turn out to be a good move, but the preliminary returns are not promising.
