Part of the problem may be the universe and the characters. With a 'formula' show, you usually have things for characters to do and to build story arcs from - cops, doctors, lawyers, etc. X-Files, for all it's alien mystery and fun, was a cop and murder mystery show at heart.
For Terminator, it almost has to be serial, with all plot related to the core storyline. I'm not sure what kinds of side stories are available to the characters and the universe, given that obsession over Skynet and the future drives everyone? Sarah Conner goes to the school bake sale? John gets a part-time job?
I would try to get them tangled up in side-stories that appear at first to be related to Skynet, but are really something else (people in trouble, bad guys vs good guys stuff). They have toyed with this, but need to go a lot further. Have some strong single and multiple episode stories that are fast, action packed and tense, but have nothing to do with Skynet. That would fit the actors and vibe of the show.