Seems cool to me, and not too strong. The dual wielder feat for ex. gives 2d8 instead of 2d6 for the same cost, and gives +1 AC. If you add your str/dex to the damage this feat would probably be better.
As it is, I like it. Makes daggers more flavorful and adds an incentive to use them instead of going for the more optimal (boring) option.
How about an app that makes calls, but you have to dial like you would with an old rotary phone.
If you make a mistake with the rotations it just connects you to a random one of your contacts.