This review contains spoilers for previous episodes of Arrow. After last week’s episode kicked this season off with a bang (or a twang… too soon?),  episode 2, Sara, starts to flesh out more of what we can expect for the rest of the season.  There are many high points, but an unfortunate weakness—that has been mostly tolerable to this point—is now being drawn to the forefront of the show. This season is establishing a much more mature Oliver Queen than the previous seasons.  Season 1 and 2 focused more on Oliver becoming the Arrow, but now he’s responsible for a whole team, not just himself.  In this episode, Oliver feels the…