How high do you value this guy?
It's not just a question of how high do a value the guy, it's also a question of how high a value a pick in the 45-60 range, vs in the 75-90 range.
I don't see much reason to trade good, under-30 players for shots in the dark. And when you get to 75 to 90, that's what you start to get.
I haven't studied it, but my guess is that you'd do just as good signing undrafted prospects as you do drafting 80th overall.
So might as well keep Luke Glendening until someone is willing to pay a better price.
If someone fattens up the offer with a legit prospect who still shows NHL promise 2-3 years after being drafted, I'd consider that.