I don't know how it looks today, but a few years ago I remember that very few people were random players. Most were organized into guilds that were travelling between servers to compete with other guilds so an interesting platform would have to be delivered that would be playable in both situations - no guilds and lots of guilds.
To produce interesting results for that item system, a small war server could be interesting with:
- relatively easy to catch up with top players exp system
- characters that save
- an economy in which players would gather lots of items in depots
- game balanced around pvp (I have no experience regarding this one)