Shaco's Backstab is kinda weak now

Hello

I just wanted to ask why did Riot made crit damage so weak on his passive? I mean on 18 level he has 150% crit damage, that's not much. Comparing it to who can have two items with 100% crit and 250% crit damage before hitting late game. This new passive kinda forces Shaco players to buy Crit damage runes, but when You think about it everyone can just build full crit build instead and have 250% crit damage. I just think that Riot should at least buff it up, up to 200% on later game or even give it up to 220% just like on his old Q passive.