Could be to do with the new character being spawned in a world/place with a higher/more dense population and that many players is demanding resources from your PC. What class did you spawn as previously and what class are you now? that will determine starting citystate location. Honestly, I've always found Limsa Lominsa to have waaaaaaaay more players in that gridania or Ul'dah. That's just my server though. Yours may be different