"May be better to move on from kessel before that contract starts to look really bad compared to his production."

Ehhh, phil had literally the best season of his career this year man... and we have him with salary retained, and are in win now mode.

also I'm a fan of Zadorov but I dont really know why either team makes that trade

Kessel had 92 points this year, and the idea to replace him with David Perron (who already didn't fit in Pittsburgh) for $1.3M less is crazy. Perron had a career high in points last year, but that's likely not repeatable for him, and it was comparable with the worst seasons of Kessel's career.

Phil had a career high but disappeared in the playoffs. Injured or not his play was unacceptable. Phil's game is based on speed and at 30 he's going to lose a step sooner rather than later. Especially because he isn't big on fitness and conditioning. Phil having a career year just adds to his trade value.
Perron didn't fit well in Mike Johnstons system which no one really did. In a more speed/skating system like vegas used he thrived.
This is easily a deeper team than this past season

Phil isn't a core player and although he had a monster year he was invisible in the playoffs. There has always been talk in Pittsburgh of when Phil will get traded. As soon as he loses a step he will not be close to as effective as he has been. I think getting a young winger and a top 4 dman is pretty decent return. Plus Guentzel is going to get paid after his ELC expires next summer and i'd rather have the few extra millions for him instead of an aging kessel.