New AD Item for the AD Assassins!

I don't have many ideas on this, but I encourage you to read this item idea because it could very well be implemented in the future. It is pretty much a complete opposite of Lich Bane.

This item, I am calling Guinsoo's Skillsaber although Riot will probably change the name if they do decide to do something like this. Basically it will go like this: After a certain number of auto attacks the next ability will deal extra physical damage.

Now the numbers can easily be changed but i am thinking: 50 AD 20% Attack Speed After 5 basic attacks, the next damaging ability will deal an extra 200 (+20% AD) physical damage.

Now the reason I think this might be a little op is because of champions like Master Yi. He will be able to easily get the 5 basic attacks thanks to attack speed and his passive, and will deal tons of damage with his Alpha Strike because of this. So the numbers will probably be tweaked if this is ever implemented but I think this could be a fine addition to assassins.