Yes, I do too. Here's something I wrote in another thread on these forums: "You know, the more I've played Dragon Age more its plot reminds me of Oblivion. Invading hordes sent by a god from another plane of existence to conquer mortal realm...King/Emperor dies in the beginning of story...travel to several cities in order to persuade the cities to send reinforcements...self-effacing traveling companion who becomes king/emperor..."
Uhh, technically speaking, neither the archdemon or darkspawn are from another plane of existence. They're always present and the dwarves have to fight them off in the Deep Roads constantly. When they all join into a huge army under the archdemon and emerge, is when it becomes a Blight.
But yes there are similarities. Get the hell over it, nobody's plagiarizing so lets not all get our panties in a bundle over the matter.