Oh come on, its not like they did it by accident. Obviously the player Dal rates and would have picked at 11 is just as likely to be there at 21, but now we have an extra pick in the 2nd round. How could that not be obvious?
That's an assumption, there's a possibility that the thinking behind the trade is "you know, player A at 11 is incredibly similar to player B at 20, no biggie to go with B, with the bonus of gaining 21", which is all good unless player A turns into a superstar and player B doesn't, then it's an issue. But that could also work in reverse and player B can end up the superstar, in which case it's genius.
But even if it is as you say (targeting the same player), then it's a bit of a gamble that other recruiting departments won't do their research/cotton on and pinch this player we have in mind between 11 and 19.
There's also a gamble that someone that Dalrymple's rates as top 5, 6 or 7 inexplicably drops to 11 (with no chance of dropping to 20).
We really can't judge this for certain without Dalrymple's actual "hit list" in front of us - exactly who he would take, and where, in ranked order. We'll get rumours of this and that, but without that list to judge this move absolutely objectively, we're all basing opinions on half cocked info. And chances are that we'll never get to see that list.
If the player we hoped to take at 11 falls to 20, and turns into a gun, then it's an excellent trade, but if he gets pinched or we had a chance to get a potential superstar at 11 and didn't purely because of this trade, and pick 21 doesn't compensate, then it's clearly a failed trade, no matter the thinking/strategy behind it.
We'll only really begin to have a reasonable idea on how good this move was by about 2023 when these possible/actual recruited players have a number of years in the system.
Until then absolutely ripping into the footy department for their "stupidity", or on the flipside, giving them pats on the back for "such astute trading", is pretty silly and premature.