Pretty Little Liars Season Finale Reveal: A Letdown?

SPOILER ALERT: On last night's Pretty Little Liars season two finale, the ABC Family hit revealed the identity of the individual who has been stalking residents of Rosewood. Stop reading now if you wish to delay your surprise.

So... that was it?!?

After months of saying her show would plot a different course from the books on which it's based, Pretty Little Liars creator Marlene King revealed the identity of A to be Mona, the same person guilty of such crimes in the novel.

Moreover, is she even A? If she simply working for A? Should we refer to the anomyous individual to whom Mona spoke at the conclusion of the episode as B?

While any season finale needs to build momentum and mystery heading into a break, this one seems to have simply pretended to answer a major question while, in reality, just extending the same question as always to this summer when PLL returns.

Won't someone still be stalking the girls? Won't viewers still be wondering who is out there? What actually changed last night?