I applaud the writers of "Batman" for introducing Barbara Gordon in her own right before making her Batgirl. With her initial appearances, we see how she can handle herself in a fight and as a detective, and it heightens the anticipation for the big reveal. As such, it comes in this two-parter which finds Commissioner Gordon framed for corruption.
It's nice that Barbara becomes Batgirl for a reason. She needs to create the illusion of Batman at the rally. It gives the show and the characters a little more depth and provides a good reason for her to put on the costume.
It's still amazing to me how much story is packed into this episode and its second part. The story of Gordon and his woes, Barbara's frustration with Batman, and Bruce's undercover work...and that's just Part 1!