Hold down the buttons = Charging it up. That's why I compared it to Balrogs turn punches in Street fighter. They work the same way. Shadow sneak won't be predictable, so long as you don't use it predictably. It will be primarily used as a punish or an escape.
Think of it this way. Lets say you constantly are holding down gren's side-b, whilst moving around and poking with Water Shurikens. Now you're able to poke at them with your projectiles, while simultaneously being able to punish theres with your teleport if they dare throw one. Just having that move will be enough to scare the opponent into throwing anything from a range.
It can also be used as an escape and a recovery too i'm assuming. Also, because his charged shuriken drags the opponent for so long, it looks like it's very possible to teleport into the opponent as they're still being dragged and hit them if you have been charging it up. It will have it's uses.
Also, I wouldn't automatically dismiss his throws as weak merely because of the range. Charizard had the longest non-tether grab in brawl, and his down throw was one of the strongest in the game as far as pure knockback goes. Only surpassed by Squirtle. Although the angle was kinda meh. :V And when it comes to damage, DDD was well known for his above average grab range, but punishing damage.
His u-smash has some hellish recovery time yea. HA! Just so long as you use them as punishes, and not spacing moves. Although, his f-smash looked pretty safe on shield. Wish I could see his down smash.