Also, another idea:
Instead of star ratings, do you think it would be better to organize series in a tier system?
Tier 1 series would be the most elite, T2, not as much etc.
This way there wouldn't be a limit on how far back we can go. So if a series is really just a mess we can ,temporarily , dub it Tier 10 or something to that effect. That way the organizers would see that their series is out of whack and we would lower the number as they got better.
It's still quite a subjective rating process but with good and vastly experienced judges this won't be a big deal.