Great ideas so far that show lots of potential for new players. One idea briefly mentioned by Ryzek above was to entirely remove the level 80 boost. I wouldn't remove it entirely but simply make it harder to achieve for new people, moving the npc into for ex. Varanas somewhere where only returning players would know about it.
Personally I would like to see players have a reason to stick around, atm once you reach max level there is little information on what exactly to do on the server, so some tips/guides on best way to get started would be most beneficial to new players as there were so many changes implemented over the years that even as returning player it's hard to know where to start, let alone as an entirely fresh player to the game.
Creating some quest series through the newbie pet or even in a fresh new UI like card/housing would be a great way to show players the game at the start, directing them into correct areas or simply teaching them mechanics of the game that were maybe too advanced for showing players in the tutorial, as there is many cool things you can do with your character in this game the higher your level gets.