| Personally, I like the idea of the portal system, it would allow for a multitude of player styles to come into the game. The only problem that I foresee with this is player population. It would require that you have a much smaller amount of servers than normal, if not just one server for the entire game, much like EVE.
Having something of this nature would spread your population, but hopefully it wouldn't spread it too thinly to the point of the whole world feeling empty. Your central world could come across something like the city Sigil from the Planescape module for D&D. |