Well this mid-season finale was pathetically unexceptional... that is until the last fifteen minutes. While the flashbacks (which have been missing for some time) suggested that we were in for quite the event, the actual content of the first forty or so minutes didn't deliver. The hunt for the copycat wasn't as thrilling as it ought to have been due to the large amount of time devoted to personal issues. One minute we're with the cops at a bloody crime scene, the next we're with Thea and Oliver talking about Christmas. I see the need for both sides of the coin, but instead of trying to balance it 50/50, the writers should have devoted more time to the mysterious copycat which would have made a more interesting story.
That being said, the stunt choreographer saved the episode from desolation with another thrilling fight sequence between Deathstroke the Terminator and Yao Fei. As always, Deathstroke makes everything better. Similarly, the fight between Oliver and Merlyn (no, Tommy is not the legendary archer but who knows what he'll become) in which Oliver got his arrows handed to him, brought a level of excitement that was missing in the episode's first half.
Still, the copycat's reveal was not as epic as it could have been due to the same reasons stated above. For most of the episode, due to the influence of flashbacks, I figured it was Yao Fei who had come to Starling City to test Oliver. When that was clearly not the case, I suspected Deathstroke - again under the influence of flashbacks. By the time the dark archer was revealed and it turned out to be Merlyn, it really didn't matter much to me. It could have been anyone at that point; the episode was still largely a waste.
It looks like the second half of the season might be set six months into the future, that would be an interesting shakeup. A lot can happen is six months, it can either be and excellent development or the writers can botch it and undo everything they've achieved in the last nine episodes. I am looking forward to seeing what happens when the show returns. So I guess the mid-season finale did accomplish what is was supposed to - it's left fans wanting more.