Play some D&D. I don't mean DDO. I don't mean Neverwinter. I don't even mean tabletop. Come up with a system, and do some freeform roleplaying. I'm sure it won't satisfy all of your needs. As it has been pointed out numerous times, you can't. Dracul has been doing some freeform DnD for years now, and we have more fun laughing and joking in teamspeak about the stupid shit we imagine than about anything else. This thread here can show you a few examples of what we've done.
http://forum.meleegaming.com/spam/dragons-in-dungeons/msg659913/#msg659913It sounds stupid and cheesy, but I suggest trying it, because it is a fun that can't be expressed in any virtual world.
Another thing we like to do at Dracul. Arma 2. Yeah, I know you've played DayZ, and in the right circumstances it has tons of potential. However, an affect almost similar in its sandboxyness to our DnD, would be Arma 2's mission editor. With ACE and a few other mods of your choice to expand content, you can have loads of fun endlessly, with all of your friends. Want persistance? Make a campaign of missions, and adjust them to your gameplay experience. Want pvp? Go head to head with your buddies in a realistic and high stakes combat enviroment, fine tuned to your desire.
Arma is obviously a graphically demanding game and must be bought, but after 3 years of it I'm still not bored.
But otherwise, the only limitations on these two games are the people you play with, and your own drive to work and imagine things.
If you want reference on either of these two, talk with Relit or Necrowave or Artyem or Blackzilla or Larry.
You can't go wrong with freedom.