Then I'd say you should try out EVE online.
It's the only MMO that I know of that comes close to what you describe; it's like ultima by the sound of it.
It does'nt have no-pvp zones, but zones guarded by NPCs that discourages players from pvp, but if you're far enough away from the guards you can do hit-n-runs and be gone before the guards have time to respond.
But it's a sandbox game alright, and there are no servers with pve only since there is only one single but huge server where every player plays; sheeps and wolfs alike.
You can chose to play as the pirate, hunting for targets and ambushing lone miners or cargo transports and destroying player ships drops some of the equipment mounted on them, not all, so there's no full loot.
guarded zones have to be very limited imo.. theres too many in eve.. ive played it... lowsec is ok but too much highsec.
Also the game is just incredibly boring it feels like a papersheet game with graphics.. flying around 100 hours to get to destinatoin...
clicking attack and yawn while fighting... u know what i mean. just staring at ur pixel sized ship surrounded by endless space flying in direction determined by "compass"... yawn. maybe if eve online was more like strartrek online but with eves pvp system and startreks combat system... then it might be fun.
There's 1 AAA mmorpg that might become good.. world of darkness.. made by same company behind eve online.. but its gonna be a more normal mmorpg.. not space.
But i cant bother waiting excitedly like a kid waiting for santa anymore.. too many mmorpg's have tried like dfo, mo to name the big ones.. then hundreds of other small ones.
its like waiting for santa and finding socks in the present... i just dont believe in santa anymore but if it turns out theres no socks in the present this time ill be really happy but its nothing im expecting from past experience.
I just dont see how they can succeed with WoD.. because of the reasons towards the beginning in the thread.