New Item: Executioner's Scythe
Executioner's Scythe +35 Attack Damage UNIQUE Passive - Executioner: Physical Damage inflicts Grievous Wounds on enemy champions for 5 seconds. UNIQUE Passive - Unstoppable Slash: Basic Attacks ignore all shields (nullifying critical strike damage and on hit damage & effects from other items when attacking shields).
One thing that has become too difficult to effectively deal with in the game now is the amount of healing and shielding. This has become such a problem that they gave Aatrox a passive to deal with it effectively. Now some people might say that you shouldn't give an effect to an item that a champion has since it will make them useless in that regard, but this is not the case. There are already a lot of items that do this: Zhonya's Hourglass, Guardian Angel, Spectral Cutlass, Ghostwalkers, and even Tiamat. This item would be no different. It's a fair item, and a hell of a lot better than buying an Executioner's Calling and not building it into anything.
her shield lasts 5 seconds, if this item allows you to hit health through her shield but without crit youre usually better off killing the target through shield with crit. That's just my 2 cents