While most of the ideas in Planescape have been folded into the Plane manuals, I wouldn't mind seeing it treated as an actual setting.
I never played previous editions of the setting, so my understanding of it is filtered largely through second hand sources and the PC RPG, but the notion that belief has greater importance and philosophical factions are the primary movers and shakers seems interesting to me.
To some extent, it's less robust than Eberron, FR or Dark Sun as a setting, but 4E campaign support is not as heavy as in previous editions, so I think it'd work.
Otherwise, let's just go with Spelljammer. It's weird enough to be substantially different from other settings and the Points of Light idea.
I never played previous editions of the setting, so my understanding of it is filtered largely through second hand sources and the PC RPG, but the notion that belief has greater importance and philosophical factions are the primary movers and shakers seems interesting to me.
To some extent, it's less robust than Eberron, FR or Dark Sun as a setting, but 4E campaign support is not as heavy as in previous editions, so I think it'd work.
Otherwise, let's just go with Spelljammer. It's weird enough to be substantially different from other settings and the Points of Light idea.