I was not at all
irritated that the Borg baby disappeared in the same episode in which it was introduced. When I saw that I thought to myself "Grandma Janeway? C'mon, don't de-sexy her any more than you already have!" I had these images of her sitting in a rocker with Borg baby looking out into a star field, pinning for Mark and her dogs.
So, yeah, they spotted a terrible
idea and eliminated it almost
fast enough (fast enough would have been removing it from the episode all together.)