Fringe was one of the best shows on TV. It was not merely one of the best SF series on the tube. It was one of the best shows of any genre.
Sad to say many viewers had the attention spans of gnats. They whined incessantly all through Season 1.
But in retrospect it was clear that the series creators were merely pacing themselves, easing their way into the "alternate universe" macro level story arc by first tackling "freak of the week" stories.
They also appear to have learned from their mistakes in "Lost," when they themselves became partially lost.