Eve v Shaco

Why is Eve allowed to instakill adcs but not Shaco? I understand they are two seperate champs, but both AP assassins, hence the comparison.

She does just as much damage as Shaco did Wards do nothing against her unlike Shaco, who is visible 90% of the time and most importantly her burst comes from the same 3 crutch items as his did.

She is also much more useful in a teamfight scenario because her shield stops her being instakilled.

Just curious as to why her burst is considered okay when Shacos wasnt?