Sometimes my friends ask me why I don't play X,Y,Z, and why I solely play EVE. I get incredulous stares when I say "It's the only game worth playing so far as I'm concerned."
Say I want to play a game that has the following features. First, there has to be PVP, but not in rigidly defined ways or prescribed areas—it has to be an integral part of the game, part of the next two features. Second, the game has to be a sandbox in some minimal senses—and not merely having a crafting system, say, which some game developers seem to think is the condition for being a sandbox. I take “sandbox” to mean that players can build and destroy vital, core parts of the game world. Third, it has to involve risk. Rewards in games mean nothing to me if there is not also risk. On my view, features 1-3 combine to transform a game into a virtual world.
It is also a plus if the game has a lot of content and minimal bugs—further conditions which exclude many newer games due to the increasing trend of releasing games in beta or alpha or in pre-release-releases where players pay to bug test and read dev blogs about someday content. People seem to love newer games, but for me, a game needs to be released—and continually updated—for a few years until I consider it worth playing. (E.g., I tend to buy Total War games only 2 or so years after they were released, both because that's about how long it takes CA to fix many of the broken features and that's how long it takes the modding community to get really established.)
There are really only a few games which satisfy these features—partly because these features identity virtual worlds more than mere games. Cross out virtually every MMORPG, even those billed as sandboxes. Some mostly single-player games involve world-building, but not in the sense where PVP is integral to the sandbox and the risk elements. So far as I can tell, besides EVE online, your options are slim. Dayz (and its clones) is one similar such game. Player interaction in the game is highly unpredictable, usually outright strange. While the game is certainly not a themepark, it is also a bit too much like a drawn out FPS with weird social interactions for me. Someday, if and when permanent modification of the game world is implemented (e.g., building and fortifying), and if server size ever sufficiently increases, I may find it worth some time.
But so far as I can tell, EVE Online is almost completely unique in satisfying my conditions 1-3 (as well as having years of content and few really major bugs). And it likely will be the only game / virtual world satisfying those conditions for at least 5 years. At least 5 years because, first, few games are in development which aim to satisfying conditions 1-3. Of those that are, many of them are from very small studios, and many likely will only have a small following upon release. Could a game be released with features 1-3 that surpasses EVE? Sure, but to match the amount of content—player created content in addition to dev created—the game would need at least a few years of a dedicated community building, destroying, exploring, fighting, etc. Devs create the means and tools for a sandbox game, but the players ultimately make a game a sandbox. So, I guess for me--now and in the next few years--my gaming choices boil down to either EVE, or nothing really.