I remember Seeing Red. According to me, it was one of the best, if not the best, episode of Season 2. At first, I thought that it was going to be a filler ep but that final scene and the general tone of the ep was like "sayeth what" (HISHE Thor :P). Now that I look back on it, Arrow has really declined in quality from Season 2. It is not because of the lack of focus, it is because the storyline itself has been weak. You had an entire ep focusing on Felicity, one of the best characters on television, and you could only come up with a generic plotline about some obscure boyfriend. Seriously?
However, the worst ep so far has been the Magician. Lots of wasted potential there. I was expecting it to have a bigger payoff. And now, you again have a filler ep about a villainess named Cupid. Somewhere down the line, I think the writers have become a little full of themselves. At this point of time, I remember every ep of season 2 knocking it out of the park. In fact, I actually do not think that there was one single meh ep in Season 2.
Sorry for the long rant. I just want this show to be where it was. The Flash has stolen a lot of its thunder.