User blog comment:Godasshole/Nero, the Nightblade of Darkness/@comment-24087642-20140430031144

2 reasons they removed evasion:

1) Riot hates random numbers. The only random number they have left is crit chance.

2) Thematically, it makes no sense, because if you're stacking evasion, you're probably a tank. And it doesn't make sense to have a heavily-armored juggernaut dodge stuff while an assassin doesn't...