I was surprised that the story touched so directly on the main plot line of the films. I have a few thoughts on this:
Obi-Wan takes an almost identical position to Luke's when he first appears in the sequel trilogy. I.e. "the time of the jedi is over". I was a bit surprised to hear this coming out of Obi-Wan's mouth. Clearly he'll need to reverse this by the end of the series, so he can be the person we see in episode IV that trains and passes the tradition on to Luke.
The thing that pulls him back into the action, i.e. "save Princess Leia", is the same call he answered in episode IV. He also pulls a similar move, "sacrificing" himself to allow the princess to escape.
The revelation that Vader survived their last meeting makes Obi-Wan aware of his own culpability not only in the failure of the jedi but in the deaths of those who have been hunted down by the inquisitors. What he does with this knowledge will be critical to the next episode. Does he seek to finish the job he left incomplete, or does he find some other synthesis having to do with the prophecy of the One? I expect this will be resolved with the understanding that it's Luke who must confront Vader.