If we got Auston Matthews, I'd seriously consider trading down a spot or two if we get a good offer, although it does depend on how they all perform over the next year. Matthews is great, but so are the next few prospects.
Stamkos is a star, but trading down for Doughty wouldn't have been a terrible idea. Tavares is a star, but trading down to Hedman could have worked too. There are some drafts where trading back a spot or two would have been horrible, and some drafts where it would have ended up with a better pick. This isn't a Crosby/McDavid draft though, and you have to trust Hunter and our scouts to make an informed decision.
Assuming we think Matthews/Chychrun is like Stamkos/Doughty or Tavares/Hedman, the price of trading down would be less than Strome, much less than their next four 1sts, but more than Chicago's 1st.
I'd say Arizona's 2017 1st, unprotected, would be a fair price. Likely a top 10 pick, possibly still a lotto pick.