i'm also a old OS player and i'm stil playing now. Since the ep4 day, when enchantement and orange stats came up shaiya became a buisness and not a game anymore. After enchants came out rich ppl owned if they werent rich they were farming 24/24 7/7 to buy GM enchance from others.
ive been playing since the first beta day and the bigest best funiest pvp ever was in ep3 mostly in karis cuz ligts used to suck ballz back in ep3 lol

look now, ep5, if you don't buy your 65+ set spending 300 bucks or if your not in the top guild farming kanos bosses you just gonna get 1 hit lol

for private server its hard
1) bcuz its not possible to make a ep3 server anymore so u must do a ep4. with or without enchantement, if you don't find the way to depatch it you can limit it to 9 or 10 for exemple or 1 2 3 etc...
2) i don't get why people wanna make custom items.
i mean its Shaiya for one reason, whats the point of looking like a power ranger or having accessori lapis with +30 stats each? go play Aion if you like pink armors and wanna fly.
3) the drops : u gotta make them easy to get if you want a fast pvp server wich means when u log in its not to farm but just for pvp. OP/LC u should make them free from item mall just like rec runes or dropable in d1 for exemple.
same for accessories, why making custom accessories? in ep3 we had best accessory sets lol and in ep4 heroics and then dreads lol.
4) even if its a private server, you need a donation system cuz even if you don't like the point a PS need people to donate if they wanna keep it up, its still a buisness u know.
so make 58 mounts 59 weapons not droping in game but for a dedicated price in item mall
also make the 59 weaps droping from cti just like it is on OS.
Look at shaiya Unknown it was so far the best ep4 server w.e people say about the staff
im talking about the gameplay. so far it was the best one, maybe u can ask the dev of it the DB they used so you have an idea abt the drops rates.
also if you do a ep4 i suggest you to dont change seraphim drops and make debuf lapis non dropable from others thingies like boxes.
just my point