While I do have to agree with hammer that the addition was a bit of a surprise, I'm sort of used to this, having read before watching ever since mid-Kabuki. Though in Owari's case it's been six months since I read the novel.
Shaft's adaptation is generally really satisfying. I look forward to some exciting things in Shinobu Mail and more in future seasons.
Knowing Hammer's a fan of the novels certainly explains why he seemed to be hooked on Ougi and on them as a couple pretty much the moment the anime started airing.