lol You can take ArcheAge off there, anyone who's played it will tell you it's one big theme park disguised as a litter box.
Anyway, you cannot have a successful sandbox without some themepark. People need goals and guidelines, whether they admit it or not. All you have to do is look at games like A Tale in the Desert or Face of Mankind to see how popular ( not ) player only content sandboxes are.
Make a good themebox or sandpark and you'll have a chance at success. Like Star Citizen, for example. It is more sandpark than sandbox, and that's one of its biggest draws. It actually has content for you to do, rather than for you to have to make it all up yourself.
This is true. In swg there wasn't any thing to do, except grind to unlock your jedi or gain experience on your jedi. It seems to me the only people who like pure sandbox mmorpgs are people who role play. Take for example swg, there were no dungeons, no pvp warzones, and no quest chains. What are you supposed to do, when your done leveling? I don't like sitting around waiting for pvp to happen. There was no questing in swg. The quest you accept generated spawns of 3-5 npc that you needed to destroy to complete. You did this over and over to level. That was not fun and swtor is 10 times better than that crap. I find it hard to believe any one would have fun in that game outside of role playing or maybe that flying, but otherwise what is there to do except craft? There is nothing outside the main cities.
I spent a lot time in Dathomir and Dantooine and both zones were always void of players. Between warcraft and swg it's no wonder warcraft won. That is why swg attempted to copy wow, but it only drove more people to leave. The game was not design like wow and consquently made little sense to change it. There was also the change to jedi from an unlock to standard class, which pissed off most of their player base.