It would be an elite center for a top line center and a young top-4 defenseman with top pair/elite potential.
If Guhle wasn't an NHL mainstay, I would say it's about fair. A 22 year old current top-4 defenseman with 100 games of experience has significant value. Most defensemen are in they're mid 20's to be as far along in development. Guhle's current development certainly has him in the top pair/elite category, whether he reaches it or not is a different story. If he were put on Vancouver today, he most likely would be on the 2nd pair, even with how good Vancouver is. As much as I hate advanced stats, jfresh has him at 94% for even strength defense this season, so take that with a grain of salt.
I'm not saying Vancouver would have to throw the kitchen sink at the trade, but I do believe in that scenario they would have to add something else.