1. focus on the economy...<--- this is rule 1, the others have neglected this, my main reason for not playing darkfall was that crappy economy.
But xsyon looks promising, just make sure to have some form of trade tools, not actual game mechanics, but something along the lines to help players sell gear, player vendors (no wow auctions please) <-- my opinion and maybe a message system etc
2. Do not focus on one aspect 2 much, so do not solely focus on one element of the game.
3. cater to all people without restricting one element, there should be choice and freedom yet pros and cons to each one.
for example, putting restrictions on pvp in a sandbox and also guilds and having safe zones on resources that others will not be able to obtain because of the games protection involving safe zones is one thing.
Implement the choice for players to protect themselves, gates, guard towers, alarms, for example a trap someone can trigger can make the others aware of their presence, and also maybe guard towers can "spot" people.
I am mostly against a complete safe zone for guilds (if it was npc related, where players could go like a npc town that would be ok, but there isn't none in xsyon), the reason behind it is simply that not only are the ones who do not want to pvp for example are protected but also the ones who pvp, which then creates a gankfest of a game, outside of safe zones with naked people because people will not risk going out or need to really go out of their safe zones to get things, which kinda makes full loot pvp in xsyon a bad mechanic and only a grieving tool at the moment.
A example of a better mechanic could be a area or a zone in the world where peaceful guilds can settle, and only blue or "good" guilds can be settled there which are safe, but there are better resources outside of these safezones which means they either work harder or take the extra risk which means they do not have to work so hard, 101 to risk vs reward, but hard work can also get you somewhere.
Also some people have said something about safe zones being optional, but who in their right mind would take on a extra risk anyway when there are so many benefits to a safe zone and no cons to them, so it still pretty much be the same result even if safe zones are optional.
4. events....keep them coming and daily or allow players to have the tools to create their own events, so fluff for example, for example Darkfall, fun hulks, MO's mini games.
5. communication within a sandbox and also reputation for players is a important aspect, mostly relating to role-playing here, it can help people to be more attracted to a game so there should be titles that players can give each other within a guild for example.
6. no more god like restrictions and features, involving you can not do this ....its a sandbox, and also talking about guild, tribe system with the virtual rules that people can have within their tribes, for example unable to terraform or even build, I think its down to the tribe leaders to control members....again not the game, but I think that there can be a light restriction of players building near a tribe for example, so a tribe could effectively build points or posts or even walls that will stop others from interfering, because it may sound like this is bad, but right now for example, people are in enclosed communities because of this mechanic, other guilds/tribes can not help each other out, do projects with each other, or help or work together because of this mechanic.
But if anything guilds and tribes should have the option to allow people to build in their lands, or be able to seek permission from the tribe/guilds.
What needs to be remembered in a sandbox is that interaction between players plays a very important part in sandbox and having all these virtual restrictions dumbs down the experience and takes away experiences that players would be able to have if the restrictions was not in place.
so yeah there really needs to be a better system in place revolving around guilds/tribes because right now the only thing is rivalry and enclosed communities within the game because people barely interact with each other and the only time when they do is when they are ganking each other out of safe zones and maybe abit of trade on the side for example.
I think that longevity within a sandbox comes from the players interacting with each other because there is no pre-set path in the game currently such as other "theme park" mmos so players need to be able to do what they want with the tools they have, and these tools should be as flexible as possible but currently the system we have is very restrictive and like chains on those tools and even if its a prelude its affects will affect the game in the future, also guild warfare it self should be there without any system to support it but there should be choice to use it when a system is implemented which has a ruleset but pro could be that you do not go red which allows for a system where a territorial control can be achieved though a actual system or players can just go all out but the con will be thqat they turn evil from not using the system andif it comes in, also pvp doesn't just mean killing each other, its about players competing against each other in terms of economy, land mass and resources and pvp has many forms, but currently the only one this game offers is ganking and who can build the biggest sandcastle by getting the most members because resources can be claimed and untouchable by other players, which means its technically a exploit in its own right since the only thing to support this is that if players actually choose to use the tribe system, but if there are more rare resources within the game in the future, people will look and will do things that will make people resent the game because others will want to obtain a upper hand and monopolise stuff and i am talking about say for example a bunch of players build safe zones around certain rare resources within the game, we now have a monopoly other the resources within the game which are untouchable to others which then again creates problems.
xsyon has to choose to be flexible in all features and mechanics and allow them to be fluid with each other because currently its not working and its easily seen by the rift within the community over such features, because the features need to be one with each other, intervened with other and connected, where one system supports another, for example crafting decay and loss of equipment resulting from pvp would help to boost the economy but effectively allowing safe zones to exists means that the economy will be slowed and nearly non existent because people chances of losing "valuable stuff" is not very high since they will not risk it and most of their resources will be located within these safe zones which are untouchable such as the players themselves.
so yeah I could ramble on all day but to have a successful true sandbox experience it needs to allow players choice and freedom with their actions and goals with the tools the game offers and offering something with chains on it is not a good thing because it restricts creativity and sandboxes live on creativity which means that its down to players to set their own goals and what they want to do and keep them interested but alot of paths this game offers are very short sighted or restricted it stops players from achieving things they want to do.
But I think that the most important thing in a sandbox is features that bring alot of content or more tools to the game for example, farming,breeding, taming, woodcutting, mining, and lots of buildings, these types of tools is what helps players come up with goals but right now there are features which are making xsyon a very boring place where interaction between players is non existent.