Duskblade and riot biases

I don't know why riot has this strong hatred for AP casters but it needs to stop. DFG gets removed i don't even remember the reason. But then you bring duskshadow in which is like DFG except for AD champions. I don't understand it riot gives AD assassins so many ways to deal with AP casters yet AP casters don't have anything to deal with them. An item that gives me armor and AP then an active that gives a shield reducing AD damage taken would be nice.