PvP servers are always going to be more populated than PvE servers. Which is why all private server projects start with a PvP server. 
  
 
  
Look, you've got two classes of players. You've got the people who played on Nost before and are level 60, and then you have new/newer players. 
  
From what I can tell, about 2/3rds of all the players currently on Nost, are new players(and about half of them aren't actively trying to level). 
  
If the Fresh server had been released at launch, who honestly believes that the Fresh Nost wouldn't have significantly more players on it than the old Nost? Which is precisely why they want to leave a month window between them. So that people would begin playing on the old Nost, in the hopes that they'll stay once the Fresh Nost comes out. 
  
  
At this point, the only way the Fresh Nost doesn't steal 2/3rds of the current players from the Old Nost, is if the Fresh server is heavily limited by queues. 
  
If there are 10k people who want to play on Nost servers, they will need to put a cap of 5k on each server. 
  
  
There is another server project, and I remember they had like five servers, each of them with a server cap of 4,000. And when you looked at the servers at the time, each of them had a population near the cap, especially during peak hours. 
  
But they then tripled the server cap, and now most of the other servers are empty.