If 90 cap, put at least 15x ~ 25x rates (just an opinion).
And make a server that players need to get united and lvl in 8/8 party.
Put new areas and objectives for players being actives: like Job Wars, unique hunting.
Rewards for pvp.
Open a temple for thiefs, hunters and traders with uniques inside to create more challenge and good drops from them.
At ctf and arena put some new rewards like coins or silk items or even special items.
Try to put egypt set to 9dg (if i'ts possible).
Tiger girl - spawn it in a new area that is restricted for 40+ ~ 60+ players (like teleport or other thing). The same thing with other lvl system restriction for Uruchi, Isy, Captain Ivy, etc.