[in_cahoots]

Looking at the top series, they're all semi-obscure or obscure, early seasons of very new shows. This means they follow some key trends: obscure things typically have higher ratings in general than the mainstream, because you're unlikely to hear about them / watch them if you're not already in some narrow niche. Compare that to something like The Big Bang Theory, where people watch it just because it's on.

Ratings also tend to go down as a show matures, both as the quality and novelty drop off (even The Wire has its critics of the last season) and as the show is exposed to a wider audience.

Taking this into account, I don't think user ratings are the best measure of a show's appeal.