User blog comment:KeithCornell/My changes to Regenerations and other stats/@comment-973379-20150405150822/@comment-973379-20150407164927

The point is - this will nerf crit. Kallista do not build crit. Vayne can live without(or at least arpen from "new" crit for triforce and Q bonus-to-AA damage will compencate). Not impossible to face, no, just "the same or slighly better"(and thay are already at the top of ADC chain) But Ashe, Cait etc depends on crits to do damage(they haven't things like Vayne Q/W, Kallista E/W etc) - and they will be nerfed by this change. So most "good" ADC will remain the same(except Cait), while some "mediocre" will become even worse - and so "good" one will be "OP" not by themself, but in comparsion to bad ones.

50% doesn't. 75%(with IE)+35%(LW)+6%(masteries)+15(runes) will.