It would be pretty hard to make the worst MMOG ever without getting sued for copying somebody.
But I think I'd start with a Newb Crafting System where you could actually kill and skin newbs to make Franken-newbie Leather Armor and cook up some Newburgers, and you'd get Hellyah Points for running around wearing somebody else's face for a mask.
You'd need Starvation to be a constant worry in order to promote cannibalism in shared dungeons with long respawns, and to keep the newbies weak and slow and easy to crowbar for crafters and folks that wanna use their bodies to spell out stuff like "U GOPT KILED!!!" and "CHUK NORS" in the streets.
And permanent death, permanent injuries, dismemberment, decapitation, sexually transmitted diseases and full frontal nudity instead of cheesy swimsuits.
Mmm, wait, this is starting to sound really good, if it had nasty rusted out vehicles it'd be a lot like Winst's Mad Max thingie.
Hmm, okay, this is harder than I thought.
Okay, maybe I should start over with some highly beloved Intellectual Property with a cult following that I can ruin.
Like... naw, that's been done before.
Man, this is hard.