Zombie Apocalypse MMO, Your Thoughts?

My fellow gamer, have you ever wanted to be a survivor in a massively multiplayer online game based on the player vs millions of death dealing zombies? It can be thought of as Left 4 Dead but with thousands of survivors per server that need to ban together to survive, build death vehicles to get around and fortified cities that can be populated. The vehicles can be made to fit multiple persons while the cities can be all guild run, and the only way to make a city is to start a guild. But of course if a small guild exists with a small city it will be a lot harder to defend against the zombie horde that just keeps coming (Since the cities will actually be destroyed if left undefended). But the larger guilds with the cities will run like a well oiled machine, with all goods and services run by either players or having the ability to hire CPU merchants for there town that will try to get regular goods, but with the help of player gathering and hunting convoys they can get a hell of a lot more.

It would seem that guild/city life would be the very aspect of the game that brings people in, but what would make people stay? That is something that would need some thought. Like what is the end game? What is the pvp? I was thinking that pvp could possibly be guild vs guild fights, declaring war on another city for resources that the city possibly holds that a rival guild would want. City defense then would be very important, and also access to cities would be limited to guild members of certain guilds, with the oppurtunity to have visitor passes to enter other guilds cities, so politics will have a heavy say in this title.

Of course for the lone wolf player, or the lone survivor there will be lots of gameplay for them as well, like first off becoming a mercenary for other players to higher and use as guns for certain situations. And the other would be the capabilities to set up small housing for there own uses, like a bank. But they would make good mercs, merchants, and companions. An endgame of this vision is still in thought, but please comment on here because I would like to see peoples thoughts and ideas, and perhaps this could come to fruition one day!