He would be the perfect fit for the 1st line if he can play RW...
Too much for a rental I agree. If they can re-sign him then I'm all for it, but I don't see how that's possible without trading someone like Kreider in the off-season. Even with Kakko and Goodrow gone it will be hard to fit him under the cap.
With an extension I would have no problem trading Kakko, Otthman and/or Perrault + 1st for him. Not all of it, but some kind of package. He's an amazing player and a playoff beast. This roster + Guentzel would be Cup favorites in my eyes.
Even as a rental I would be fine with giving up a lot. Probably not the prospects mentioned, but a 1st++ sure.