The population status is counted as percentages of the total server slots taken.
Let's say that Gav has 100 player slots. That means that 100 people can be online at the same time. If there's only 40 people on, it will be Standard Population.
However, Dalborra has 1000 player slots. If there's 250 players on, it says it's Light Population.
So the status actually tells you what % of the server slots are occupied, not how many people are online.
The reason RP servers have less player slots, is because RP is nowhere near as popular as PvE and PvP, so EAware did not want to spend the same amount of money for something they did not need. Even as the current status is, you barely have any players on Gav, which means it was an accurate prediction.
Sounds correct, but... has this actually been put up somewhere or...?