As you may know from the original series, their fun and adventures of their daily lives continues on by 4 adorable 3rd graders and 1 big carefree sister. As a group, they continue to entertainment themselves from the activities they do and the things they say on a day to day basis and for us, its joyful entertainment while we are being amused by their vivid imagination and events in which they occur.
No doubt, this series could easily turn out into another 12 episode series where more fun and games can be introduced into their daily lives. As long as they keep the activities different, I don't see how it will fail.
In conclusion, a good way to finish up the whole series in general. While there no real ending, you just can't help but imagine what new adventures they are up to next.