By the time 4E came around maybe even 3E didn't they get rid of the Para-elemental planes like the plane of Ash and Magma, etc? Haven't paid all the much attention to the planes in a while
It's been so long since I read Planescape but this sounds kind of how I remember them. They weren't necessarily full-fledged planes but where the borders of two Elemental Planes bleed into each other at their borders. I could be misremembering though. Regardless I always thought at that point things were getting a little carried awayThe para-elemental planes are back, sort of, as "border regions" between the big four elemental planes. Although they aren't technically planes of their own, they're basically the same in all but name.
My point is that the Great Wheel cosmology is bad, because it was created out of a desire to make planes based on alignments, and then trying to fill them in without adequate inspiration (which is why so many of the planes are similar). There are many better ways of making a cosmology, such as the 4e World Axis or the Eberron orrery.Yeah, but all of those are spinning inside the Deep Ethereal! It's just a zoom in on a part of the Planescape that the above map doesn't detail because it's prioritizing Sigil and the Outlands over the Material, Echo, Transitive, and Inner Planes.
The Great Wheel is wondrously, Byzantinely absurd...which is why it is perfect for D&D.My point is that the Great Wheel cosmology is bad, because it was created out of a desire to make planes based on alignments, and then trying to fill them in without adequate inspiration (which is why so many of the planes are similar). There are many better ways of making a cosmology, such as the 4e World Axis or the Eberron orrery.