I have a great idea. Lets duplicate the concept of \"planes\" exactly as they\'re described in D&D, because that is the only possible real definition of a plane.
Furthermore, let us associate these \"planes\" with bland, overused themes.
Sorry that I\'m sarcastic, school is breaking me at the moment :-/ To me, the currently understood geography of the PlaneShift world allows for a lot of \"setting\" diversity, and as Axsyrus said, a few portals to other worlds should be \"more than enough\".
I do object to the idea of each plane being heavily themed towards one race, element, etc. - I think that other \"worlds\" would probably be very diverse. With regards to magic, the source of magical energy in Yliakum is some combination of the glyphs (which seem to be universal) with the manipulation of energy of the crystal, so I would suggest that perhaps while the strength of magic does not vary, the availability and type of magical energies might.