Science Fiction shows are being made in such numbers now you might think they were becoming mainstream. As a scifi fan I'd see that as a good thing. But a lot of these shows don't seem to last very long. The Sarah Connor Chronicles and Dollhouse both only made it to two seasons. V's audience has plummeted in just the first 4 episodes. Stargate: Universe isn't pulling in as many viewers as Stargate: SG1 managed. While Heroes has survived multiple seasons, it's ratings are a shadow of what they were initially.
The Story Arc
The series that solidified story arcs as a valid method of tv storytelling was of course the scifi classic Babylon 5. Adoption was slow initially, but we now have shows like Lost and BSG that almost have to be watched as part of a larger arc if you want them to make sense. Even the continuity light shows like Chuck or Warehouse 13 generally have a season long story arc these days. Each show stands on it's own, but there's some hints at a larger story as well.
I'm a big fan of the story arc. Done properly it creates a much richer story than can be achieved in the standard 45 minutes. But there are a lot of downsides. My wife and I fell behind in watching Lost during the second season and after about a month realized it was just more trouble than it was worth trying to catch up again.
Grim and Gritty
Back in the 80's and 90's there was a big fad for "Grim n Gritty" superheroes. Fortunately it seems to have faded in the last decade. Unfortunately that same trend has infected my scifi shows!
Battlestar Galactica showed that stepping away from the space battles and focusing on characters who aren't purely black or white can produce some intense viewing. But that doesn't mean every single character has to behave like an ass.
As part of the trend towards a more realistic presentation, quick cuts and shaky hand held camera work. Done well this can add to the tension of a scene. Overdone, it is intensely annoying.
How About Making It Good?
All of these techniques have been used successfully before but they aren't what made Lost or BSG a success. Strong characters, a plot that pulls the viewer in and high production values are what actually made those shows popular. None of these elements are actually required to make a good tv show.
Wouldn't it be much better to create a show that is true to itself? That has a style that enhances the story it is trying to tell rather than mimics the latest fad? Wouldn't the show do better if it wasn't pretending to be something else?