Well its fully possible it that the Shuriken buff goes away if you're within 10 yards just like it doesn't do double dmg. Shadow dmg auto attacks are nice but no ones going to die to a rogue spamming toss auto attacking with no finisher. It sounds interesting and fun for sure but I would rather have a 12sec shadowstep but this is what they want to do for mobility....
And its not at the cost of nothing if you take toss you get more pressure at range but lose burst in melee range. Which makes it more balanced. A lot more than is now as you trade burst for a little range dmg and range snare. We look to be going the dk/pally mobility model long cd gap closers and range dmg.
Which is odd to move a rogue to but they can make it work.