I get you if you are complaining about CW, the channel that does Arrow, Vampire Diaries, Smallville, Nikita, Pretty Little liars and so and so on with shows targeted towards teens/young adults. Its generally filled with limited actors chosen for their looks (basically "models" just a step above daytime soap level). But I wouldnt certainly accuse you this of this show so far, its nothing new that a new unknown actress is chosen for a show, especially a Whedon show. Though if it was, so what? Its based on a superficial medium like comics, and a Marvel one to boot.
And she isnt that hot, you kinda exaggerating if it distracted you that much.