Why doran's shield is not gonna get buffed
It singlehandedly makes melee supports unbearable whenever it is decent due to giving them high resilence to harras combined with high sustain.
Riot did this 1 time in preseason 4 and all you ever saw was Leona Thresh Annie, so unless they manage to find a way for doran's shield to work on melee carries (or toplaners) without making tank supports broken, they will not do the same error.
