Change Shaco's Backstab to a more meaningful passive? Or a bonus passive on Shaco?

Shaco is feared by players and Rioters alike but we can all agree that he has situational unreliable damage at different times of the game between his Backstab, Jitb, and his clone. But I want to focus on his passive for now. Backstab can be very strong in early game ganks where the enemy will be running away from you or when they are caught off-guard. However, it becomes underwhelming when the laning phase ends or if the enemy you're fighting grows exponentially strong. You're forced into this "enemy not playing defensively/can't handle 2v1 then take advatange if not then hope you can farm jungle to be relevant and take objectives". Most of the time you'll make use of Backstab with only Deceive and Two-Shiv as that is the most memorable thing Shaco players know to use (throw E when the enemy is running away).

I think it would be in Shaco's best interest if Backstab would instead only work on his abilities and then give him a scaling passive(either bonus damage or attack speed that becomes stronger as he levels) so that he has a bit more flexibility.

I have a poll up for you're opinions:

1. Backstab will only work with ability damage while he gets a scaling passive
2. Backstab should be replaces with a new passive
3. He is fine as is.
4. Other(specify in comments)