Of course, a lot of questions are unanswered when it comes to a series that takes place between 2 movies. 
Imagine... vice versa.
They're doing it for Futurama. The series ran for 4 years, then they stopped. Years later, they decided to bring back the series with an advanced storyline... but that storyline need an explanation for what happened during the years in between. So, they're releasing a few DVDs before they bring back the series to answer some questions beforehand. 
For Terminator: The Sarah Connor Chronicles, those unanswered questions may not be fully resolved until the entire series is over. That might not be possible considering the writers strike that we have going on. For all we know, the series might be canceled before it continues. 
