Board Thread:Oblivion/@comment-24.182.147.198-20140306210804/@comment-14027812-20140306214625

The power and weakness thing was designed to balance the game; the more your powers aid you, the more your weaknesses hinder you. It was employed to avoid overpowered characters. Think of it that way: the less blood you get, the more hungry you get, and your vampire body gives you the means to satiate your hunger, in the form of vampire powers. When you feed, the hunger diminishes and yor body returns to (semi) normal state.

Also, the racism in Skyrim tends to deal on social matters, not on the races' effectiveness.