To liken this to a fine recent example of a #2 overall pick...
Imagine, the Colorado Avalanche draft Gabriel Landeskog 2nd overall, and then he goes back to junior, gets injured, and misses the remainder of the year. They decide that, they need a defenseman instead of another forward, having a gluttony of forwards at their disposal already. Take, for example, they still have their #11 overall pick at last year's draft ... they then take that pick, Landeskog, and flip the two of them to the Jackets, in exchange for the #2 pick and the right to draft Ryan Murray.
Colorado: Ryan Murray
Columbus: Gabriel Landeskog + Filip Forsberg
Does that sort of a deal look so good now? I think that would be the cost to move up to #2 or 3 and select Nathan MacKinnon or Jonathan Drouin. Let's say that, there's a faller like Forsberg in this year's draft ... for argument's sake, I won't even use a guy who's slated in the top-4, as Forsberg was last year ... let's say Lindholm falls to our slot at #14, but we've dealt Murray and that pick to, say, Florida, for the right to draft Nathan MacKinnon.
Florida: Murray + Lindholm
Columbus: MacKinnon
Just for some perspective. It's also in my opinion that Florida and Tampa are going to be pretty high on the players that fall to them, and both organizations could use more offensive help. Say what you want about Tampa, but they have some aging stars, and could use some youth up front. What this means to me is that, we would probably have to include even another piece ... likely a young, fairly cheap roster forward.
It is for these reasons, above all else, that I'm against trading Ryan Murray. If the cost is straight up - Murray for MacKinnon - then you consider the deal. But not if we're including another piece ... at all.