I live in Phoenix and have had a chance to watch every Coyotes game this season so I thought I would chime in here...
Wolski is a perennial underachiever which is why Colorado, and now Phoenix has unloaded him. While he has potential, the time is running out on him to finally become a reliable scorer. Plus, he has a bit of a hot head and is ultimately why the Avs traded him in the first place.
Phoenix now has better depth on defense, which they have lacked since losing Zbynek Michalek to Pittsburgh. They needed a puck mover and someone they can slot into the powerplay and Roszival is that guy. Now they can give Lepisto, Schlemko, and Ekmann-Larsson some additional nights off, as the three have often rotated in and out of the third defensive pairing.
Good deal today for the Yotes, and in my opinion, if Tortorella can't get Wolski going now, nobody will, and he will be out of the NHL in a couple seasons.