The show is still not perfect, but they did fix several things. The Dinah character was retconned into not being Dinah Laurel Lance, the Black Canary. She lied about her name for no apparent reason. Now she's Dinah Redmon, a completely new character. Sure, this gives her no reason to actually be with Oracle and Huntress anymore, but there was no reason before anyway, and at least now they aren't bound in anyway, by her comic book history. This also served to make her less of a goody-two-shoes. In fact, she blatantly disregards authority a few times in the episode, making for a much better mentor/student relationship. She also has much better hair now.
Huntress/Helena's character has also been tweaked slightly. Now she comes across as much more bitter and much less brash. She's not the same loose canon character as in the comic, but she makes much more sense as a character in the context of the TV show.
Mia Sara's Harley Quinn character is still one of the low points of the show to me. She's over the top in the wrong way. She strikes me as a spoof of a Buffy villain (Glory, in particular) more than a character in her own right.
They also seemed to have realized that they could color the world much better by relying on some of the existing Batman mythos. As such, Barbara drops a passing reference to the three Robins, that Helena understood, and yet wasn't really integral to the plot.
All in all, the acting and writing were much better this episode, as were the special effects. I wouldn't expect it to win an emmy anytime soon, but it showed definite improvement over week one, and hopefully things will continue to get better.