Kassian reminds me a lot like Dustin Penner, often lazy, inconsistent, unmotivated, and takes a ton of unnecessary penalties. The only difference is, Kassian plays more physical and is a lot quicker on his feet. I could see him having the same point productions as Penner, hovering around the 40-50 points mark. People need to stop thinking he'll turn into Bertuzzi or Lucic. When Todd and Milan were at his age, they already had their breakout season. He still young, but I don't see him being "that guy" everyone hopes he will be.
Tanev is one of those defensemen, no one really knows about, aside from Canucks fans. So, I don't see him having much of a trading value. He's reliable in his own zone, but that really where it ends. He could step in into a top 4 role if someone is injured, but realistically he's a 5th or 6th defensemen. There's really nothing special about him, think Murray Baron or Scott Lachance, when they played, the unsung hero, who everyone loves. Stanton could easily replace him.