1. The flashbacks are pretty clever as a narrative device. Throughout the show, we've been presented with Oliver Queen in his "I play rich turd by day, but at night I'm an arrow-shooting vigilante" form alongside his "rich boy left alone on a dangerous island full of mercenaries, warriors, and military wackos" form. This is hardly the first time we've seen this sort of thing (Lost had its own version of it, and shows like Heroes, X-Files, and so on have played around with the tactic), but the amount of attention paid to these flashbacks -- as narratives unto themselves -- is at least noteworthy.
I particularly appreciate the attempt to connect what is happening in the present with what has already occurred; there are moments in Season Two, for example, in which the present only makes sense if you know what has already occurred, a fact that is punctuated by the slow development of these narratives in side-by-side fashion. Season Two even goes so far as to sort of "retcon" Oliver's original "story" about what happened on the island, revealing that even we, the viewers, have been lied to. It creates a great deal of tension and puts the past and present in conversation in a way that may actually be quite unique (or at least rather uncommon).
2. I've been genuinely surprised by the quality of the action in this show. By comparison to Agents of SHIELD, whose action sequences often seemed lazy and dull (normal TV fare) in the first few episodes (it improves by miles as the show develops), Arrow is slick and, at times, brutal. This, of course, serves as an excuse for the various "fit" characters to prostrate themselves in glorious gladiator fashion. Muscles and tight tummies are glorified to the max. The show also gives play time to its less trained members, such as Felicity and Roy (the future Red Hood), the latter of which is some kind of parkour ninja. I love that this isn't just a show of muscly people punching really hard, but of muscly folks actually having to be competent at what they do (mostly).
Arrow doesn't always get it right, though. I think the choreography and editing for Sara Lance's Canary fights have lacked the same intensity as those of Oliver's/Arrow's. I'm not sure why there's such a marked difference. Lance is supposed to be just as trained as Oliver, if not more because of her association with the League of Assassins. So she should be quick, agile, and brutal. But there are moments when her action sequences seem out of sync or slowed down. Maybe this has to do with the fact that Caity Lotz hasn't had the same character foreknowledge to be prepared, or perhaps they simply put less time into her physical presentation because the Canary is technically a secondary character, and one that probably won't stick around for too long either because of her association with the League of Assassins or because Arrow intends for her to take the mantle of the Black Canary (no, not this), which was originally Laurel Lance's superheroine role in the comics. As much as I love her character, I do feel that there's something missing in how her physical self is portrayed. My hope is that they will correct this.
3. I am at a point where I can honestly say that I despise Laurel. She was a sympathetic character in Season One, but since the death of Tommy, she has spiraled down into a pit of alcoholism and general asshole-ish-ness. It would be one thing if she were only destroying herself; however, throughout the first half of the second season, she's been oblivious and, at times, downright vindictive.
I don't know if the writers thought it would be interesting to switch the roles of Laurel and her father, but that's certainly what happened. Except, Laurel's transition does not make her sympathetic. Sure, she's begun attending AA meetings and trying to get her life under wraps, but even in her sober state, she's just not a likable character. In some sense, I think her post-sobriety personality is less complicated than the Laurel of Season One, and that makes her less likable and far less interesting. Worse, she's untrustworthy, flipping back and forth between standing by the people she loves and stabbing them in the back -- granted, her stabs are less mean now that she's sober. It's just not a good path for the character.
The father, however, has become a lovable figure -- loyal to friends and family and loyal to the Arrow (at first for reasons of necessity -- the police won't let him do his job -- but later due to a kind of shared trust; the scene where he monologues on why Laurel shouldn't tell him the identity of the Arrow was probably my favorite moment from him since I started watching the show).
4. Oliver Queen's character development is going to hit a wall pretty soon. And that wall is "the present." I like Oliver. Sure, his present self is rather simplistic in the aggregate -- one-directional, if you will -- but given where he began in Season One (vengeful vigilante/murderer) and where he ended up by Season Two (vigilante with a code of honor...sorta), it's hard not to sympathize a little. The problem I have with Oliver, however, is that his growth in the present is far surpassed by his growth in the flashbacks. We *know* where Oliver ends up as a result of his time on the island, so every time we see how he responds to past events, we also see the incremental growths that will eventually give us "present Oliver."
But Oliver in the present doesn't seem to have grown all that much. While he no longer indiscriminately kills in the service of justice, he does consistently devalue the input of his friends (specifically, Diggle and Felicity) to the point where you'd think he would have learned the "strength in numbers" lesson a long time ago. This is fine for the first few instances, but the more I see him do this, the more I find it frustrating as a plot device. It's predictable. Some crazy thing happens that affects Oliver on some personal level; he responds by ignoring his fellow vigilante friends (their desire to help, their advice, all of it); things go terrible wrong and he skulks back; the friends say "what up, man? You should listen to us"; Oliver says, "You're right. I sorry"; then they all defeat the bad guy or whatever and we repeat the cycle again.
The show can't sustain this indefinitely, so it either has to start moving Oliver forward in the present or it has to admit that it's more interesting narrative is the one concerning the island. If we end up with the latter conclusion, then there's really little point to Arrow. Not a good thing.
5. The fact that John Barrowman is in this show and plays a villain (Malcolm Merlyn!) brings me so much joy that I cannot express into words. So I give you a gif parade:
That said, one thing I certainly disliked about Merlyn's return in Season Two was the ease with which he seems to have been dispensed by Moira Queen -- she threatens to hire Ra's al Ghul to kill him. Given his control over her throughout Season One, I never quite bought the idea that this would have much effect on Merlyn, or, at least, not enough of an effect to send him on his way. What was the purpose in bringing him back if he's going to be shoved away without much of a fight?
Now, perhaps what I'm seeing is setup for a huge reveal, in which Moira Queen turns out to have been far more involved in Merlyn's doings that Season Two wants to let on. And that would turn Moira into a different kind of villain within the show's cast. That, I think, would be quite interesting.
6. Speaking of Moira Queen: I love that this show is never afraid to complicate the family dynamic. In Season 2, Moira Queen is revealed to have been more "involved" with Merlyn than previously thought, which puts Oliver in a complicated position as the vigilante moral judge of the city. How does he choose to deal with his mother when he knows her lies could very well tear his family apart? The fact that Arrow puts so much attention on the characters and their relationships sets this show apart from many of his superhero predecessors.
For example: remember The Cape (2011)? No? That's OK. I remember liking the first episode because it was a lot of fun, but when I look back on that time, I realize that all I can remember about that show is that the guy beat people up with his cape. That's it. I don't remember anything about the characters (other than the fact that Keith David played someone in it, and Keith David is amazing). The show got cancelled for a reason: it lacked the emotional depth that other superhero or sf/f "crime fighting" shows like Arrow or Supernatural developed.
So long as Arrow can present these dramatic elements in a way that his both logical to the characters and also doesn't interfere with the overarching narrative (i.e., disrupts without purpose), I suspect it'll keep being good.
And that's all I have to say at this moment.