Empire players do not control a single entity... They must manage their entire empire. I simply call the 'leader' character of an empire a preferred character to differentiate between these characters and the characters of singular players.
Empire players also can not focus on their preferred characters all the time. It will stunt the growth of their empire and ultimately lead to their downfall. If they always gear things to be beneficial for their preferred character, then only the preferred character will really be getting the best benefits while the rest of their empire gets weaker. Empire players must maintain a careful balance between keeping their empire safe and keeping their leader, or preferred character, safe. At times, it may be beneficial for an empire player to sacrifice their leader in order to keep a skillful bounty-hunter player or another empire off of their backs for a little longer.
Single character players only have their main character. While they may have followers, these followers may not always want to do as the character does as the character's word is not absolute. If the character's word was, in fact, absolute... Well, then the single character player would be ruling a small empire now, would they not?
Basically the two player types appeal to two different types of RPers. Empire players are geared more toward those looking for dominance or enforcing universal peace/stability. Single character players are geared more toward those looking for pure RP.
Anyways, if there is indeed a map then we need to understand three basic things:
1) It will not be a universal map
2) The Milky Way galaxy will be included and it will not be fully explored
3) The map will most likely be constantly expanding or changing in some way
As for history... I quite like the multipurpose barebones shell of a history that I thought up...
The human race abandoned Earth after the planet was drained of the majority of its natural resources. Technological upgrades since this point have ensured that planets need not be stripped bare of resources anymore as most everything can now be reclaimed. Now branching out to the remaining useable planets in the Sol system, the human race finds itself entering an age of turmoil and chaos. The transition from Earth to the vast reaches of space have been hard on everyone and, due to the open nature of space, all major governments have crumbled under the pressure of keeping their populace in check. Several independent factions have splintered off from the main populace, heading into the vast outreaches of space to start their own colonies where they can remain unbothered by attempts to start new governments, or perhaps to gather strength to sieze control themselves. No one is truly certain of the intentions these factions may have or how they intend to survive as space technology is highly primitive and inefficient even though it is incredibly cheap.
The prospects of a government rising to power, with most scientists in private employ, is very grim. Corporate control, however, seems to be the direction things are currently heading in, what with businesses already vying for control of planets like Venus, Mars, and Jupiter. Quickly built, and very primitive, orbital stations are now the main habitats of the human race. Unrest among those who opted to remain in the Sol system skyrockets due to a lack of resources and now-primitive technology hampering the development of planetary colonies. As time goes on and conditions show no sign of improving, talks of war spread like wildfire.
Soon the inevitable happens, a group of people opening fire on a corporate convoy and stealing several freighter class ships full of supplies. Similar occurances plauge shipping routes as word of this attack spreads, piracy rapidly spreading. Suspicion and paranoia between companies rises, soon reaching critical levels. Companies start to consider war as the attacks become more frequent, requests to cease going unheard. Eventually war is declared, every company denying guilt and blaming every other company for the piracy. While the war has spurred technological advances, it only seems to be gaining velocity and force. The independent factions have still not been heard from, and are all presumed as dead or lost in the reaches of space.
Everything we have so far, mind you, is not set in stone. As long as everyone agrees with it, rules may be edited, tweaked, removed, or added. This process, of course, will be stricter than even the policy on restarting the RP itself. I suggest a 75% majority and two consecutive majorities be required.