MY 2 cents worth . After managing a pserver for over a year , here is my take :
Players will stay on a server where uber is "earned" . Instant PvP is instant fail . Those servers as we all know come and go with each moon phase . They attract a lot ( not all ) customers , who don't appreciate the results of a disciplined effort to create their own build of toon. You don't value what you don't have to work for.
There are hundreds of little families of Shaiya players who travel together . They appreciate a enjoyable social setting . They relax and unwind by farming , helping each other and yakking on Skype . Having valuable quests , worthwhile farming areas and Raids for Boss's are what they live for. You attract them by creating these areas and make them worthwhile to occupy their time . Instant PvP servers have huge amounts of tension and not much to do thats worthwhile when you want to relax and get away from PvP .
Having items like 30 day ress runes , teles , PIDS , EE , and move/summons runes available for free are key to keeping gameplay interruption free and free of losing a toon.
Making higher level lapises farm able , but not too plentiful helps keep players busy and happy.
Making sure the higher level gears drop enough in game to satisfy your population is key to keeping prices down . I have seen so many servers fail because Admins restrict the flow of the economy . Its all about supply and demand , and too many Devs do not get it.
Keep PvP hot by making sure Hi-Demand items drop from Bosses . And find a common area to have the next highest items drop to create a zone of constant pvp . That way when there aren't any bosses , they will gravitate to this area . So many servers spread drops out over so many areas on pvp maps , it actually encourages solo hunting of weak players by uber players . Uber pvpers need to be magnetized by drops in a specific area to keep them happy and in pvp with other uber players , not out raping noobs. I have learned this the hard way .
Don't create items that give a donator an unfair advantage . Instead , make these rare items drop from ingame bosses in limited quantity , AND have them as a donator item. This way , if a donator chooses to , he can get uber faster , but not have an unfair advantage.
Be sure to make gear drops that are graduated thru the maps , so players can get the gear they need to kill THE NEXT level of mobs. I have seen some servers that were so poorly planned , that you had to kill mobs that were too hard to get the next level of gear, using the gear that was available to them on easier maps.
The key is to make the gear available that they will need to kill on THE NEXT map on the easier map.
This is already a wall of text , so I'll stop :P
THE BEST EP4 SERVER EVER - Shaiya Exile -by LilproHacker