- Customisable GUI. I hate having to be restricted in to what some playtester / designer thinks best;
- No 'banking' system. I hate it how items mysteriously appear thousands of kilometers away. If ppl want to move stuff, let them arrange transport;
- Single, or extremely limmited ammount of servers. 'winning' in a sandbox game means nothing if people just go and play in another sandbox.
- Player driven economy, aim to make everything that you need craftable by players;
- Diplomacy options for Guilds (declarations of war, alliances, non-aggression, tribute

);
- Allow casual / new players to be usefull from day 1, even in fights with players that have been playing for years. Wether it's a Navy Seal with a sniper rifle or a Korean highschool-student wielding a pistol, you still gonna die when shot good.
- Range of inner-Guild options, like: last date/time online of member, location, class, level, Guild Roles granted (like who can build / expand guild-buildings, managing guild-funds, etc).