IMO doing whatever it takes to make sure we don't ruin all of our top prospects (and keeping Hayes is key to insulating them) is far more important than whatever mid level throwaway prospect and late first we get in a Hayes trade.
We already have one of the deepest prospect pools in hockey, but as always we lack in high end elite gamebreaking talents. Whatever prospect we'd get in exchange for Hayes will certainly not be that. Nearly every prospect outside of Forsberg that was traded at the deadline hasn't proven to be worth much of anything.
And Clark's track record in the 2nd and 3rd rounds doesn't exactly inspire confidence.