This definitely opens up possibilities I've always considered. I've always humored myself with the idea of "What if Nintendo added this item in? How would this affect the entire game? Would it be important throughout the entire game?" I have racked my brain for days at a time thinking of the perfect item that could fit in the Zelda formula as the boomerang, bombs, or the bow. Its use could surpass even the hammers' (which happen to by my favorite non-sword-related item) use and ability; the scythe.
Many games have utilized this item. Once a farmer's tool, it has taken on the role as the weapon of Death himself. Many games have decided to add it to its arsenal of items. One such example is Darksiders (and its upcoming sequel). The item can perhaps substitute the sword as a weapon of primary choice, while still having to take the backseat in some cases. One major reason why the hammer has not been my first choice when an enemy comes my way is the slow start up. I would need perfect timing to make contact - too early and I miss, leaving myself vulnerable, too late and I take damage. However, the scythe - with its lightweight - would not have such an issue. By taking on speed, it may end up sacrificing damage. This may be enough reason to use it for smaller enemies, but let the Master Sword go to work against bosses.
Now, what exactly would make this tool different from its usual form? Darkness. The Gale Boomerang utilized the power of the wind, the arrows of Wind Waker utilized fire, ice, and light. This weapon would cause damage, and shroud Link in darkness - hiding Link from the enemies. When would such an event really be useful? Well, there are multiple occasions for this. In the event of Link having low health, he could create this dark fog and make a clean escape. In the event of having to hit a specific area of an enemy to do damage to its weak spot - an Armos for example - the shroud would leave them confused as to Link's location while he pinpoints the area that would cause damage to the enemy. This would make it an invaluable tool in evasive maneuvers and end longer fights much faster.
Like all items, it must be obtained in some way. Alongside this hypothetical item, a dungeon would also be constructed. To compliment the actual use of the Scythe, there would have to be a problem for the scythe to be useful. Such an event would be Link being without a sword. This such an event would open up a possibility for a dungeon in the Silent Realm. In order to make a quick escape, Link would need the use of the Scythe in hopes of escaping certain death.
Now, all of this is all I want to happen, but I doubt it ever will.