I'm not proficient with the rogue class, but just wanted to comment in general. Shadowstep looks almost to good to pass up, atleast while leveling and for pvp. With rogues now able to 100% return to stealth after using sap (I think it was only 90% before), using Shadowstep to sap is awesome. Why? Because it has a 20 yard range. To be 20 yards away from the target and within one click be in a rogues favorite spot, behind the target, just seems cool.
Personally, I'll hate it as a mage, but the talent is great for the class.