main server as it is..
sub server - non pvp 80% exp - no invasion, no mercenary... 0...
if u`re a slick in main server and still want to lvl up beeing afk you can do it in sub server but punished as well.
The summy is already balanced for end-game, but you have a good point, indeed. Maybe we will boost a bit the % rise for summ staffs, but this will happen anyway in end game. But it's good that you brought the subject. Thanks !
two sub-servers
only first sub-server to have invasions (golden inv, rabbits, ww etc.)
second sub-server to have no invasion but 20% bonus exp for 1-250 lvl for example so newbies can catch up
second sub-server to have 20% more zen drop (or even jewel?) to attract all alts here