I wouldn't mind a theme park within a sandbox. Kind of best of both worlds. That I could easily be happy with.
Could you please explain to me how that would work, the mixing of Sandbox and Themepark, for the life of me i can't wrap my mind around that concept. See to me all sandbox designates is the ability to affect the world and players in the world whereas Themepark is the opposite, your being in the world neither effects it or I.
Example, In EVE if say i go to a certain sector and mine all the Golden omber from the zone its gone until the server resets at 7am est. You arrive looking for the same mineral after me your choices are mine something else or go somewhere else, I've directly affected your gameplay, whereas Themepark what 2to 5 minutes of waiting for a quest completion ( you beat me to the blue flashing panel i need to click ), you beat the FP i'm gonna run, not gonna effect me will it.
So how do you combine the ability to affect the word around you and others playing without affecting the world around you and others playing ?
If you're speaking of features like , housing, weather,ect.ect. Well there just features neither belonging to nor defining of either genre. My opinion of course.