This is how I prefer to portray the D&D cosmology

I've been thinking long and hard about how to portray the D&D Cosmology and decided that I prefer a mix of the Great Wheel and World Axis cosmological models with the Inner Planes connected to the worlds of the Prime Material Plane via the Ethereal Plane and Elemental Chaos while the Outer Planes are connected to the worlds of the Prime Material Plane via the Astral Sea. I prefer to keep the concepts of the Phlogiston and Crystal Spheres as a way to connect the worlds of the Prime Material Plane to each other physically. I also want to bring back the Positive and Negative Energy Planes along with the Quasi-Elemental Planes because an Undying Pact Warlock would be perfect for surviving in the Plane of Vacuum.

The Domains of Dread are an in-between space between the Ethereal Plane and the Shadowfell because of the Spellplague while the Domains of Delight are between the Ethereal Plane and the Feywild.

The Dark Sun setting is incredibly isolated from the rest of the Prime Material Plane as it's location within the Phlogiston is far from the Spacelanes of the currently known spheres and it does not connect to the Astral Sea, one must either find it by traveling in the Phlogiston, the Deep Ethereal or the Elemental Chaos. It has it's own Elemental and Para-Elemental Planes akin to Eberron's separate cosmology.

Eberron is connected to the Astral Sea but there is a barrier that prevents entry into it's wild space system from there, you can only enter by finding it in the Phlogiston and the Deep Ethereal. Worlds from third party material can be visited but you have to find them via Planar Travel or Spelljammer, some worlds like Orden (MCDM) or Midgard (Kobold Press) exist in isolated groups of Wild Space systems, mini multiverses in their own right. Spelljammers can travel through Wild Space, the Phlogiston, the Astral Sea, the Ethereal Plane and the Elemental Chaos.

Uh, you might want to throw in a few more periods and commas, and perhaps a line break or two. As it stands, that's a really difficult to read textblock

I get you op, and Davyd's punctuation observation aside, it is a pretty standard reading of how those planes work.

The main difference in the World Tree Cosmology and the Great wheel is mostly layout, as everything is still there, just put in different relations to Toril. Then there was the spell plague, some planes shifted blah blah blah leading to the world Axis Cosmology.....

Which was then pretty much discarded during the second sundering leading into 5E, so we are back to the great wheel again, and your schema makes sense. 
Though i tend to use slightly altered cosmologies in my home games so i can add in plane and realms that are new for the players to explore and chart when they are doing a scholar or exploration campaign. 

Yeah, I really liked the concepts of the Para-Elemental and Quasi-Elemental Planes along with those of the original Spelljammer and Planescape. While I felt that it would make sense to have Ravenloft as it's own plane while keeping the Domains of Delight which were a cool idea.

I'm a big fan of the Great Wheel in a non-literalist sense. Instead it describes how the planes relate to each other. In my cosmology there are the Inner Planes and Outer Planes. The Inner Planes consist of:

• The Material Plane and it's two mirror planes, the Feywild and the Shadowfell
• The four elemental planes
• The interstitial elemental planes, each of which that exists at a nexus of two elemental planes
• The ethereal plane

"Surrounding" those planes in a non-literal sense are the Outer Planes, consisting of the various alignment planes. Each of those exists with the Astral Sea, which also bridges to the Material Plane

Then "outside" of this Great Wheel model is the Far Realm, the plane beyond planes. Additionally, at what could be described as the "poles" would be the positive and negative energy planes. Magic/life force flows into the great wheel from the positive energy plane and out of it to the negative energy plane. The Feywild and Shadowfell exist metaphysically closer to the positive and negative energy planes respectively.

Then there are demiplanes and subplanes, such as Ravenloft, a demiplane within the Shadowfell, or the Domains of Delight within the Feywild.

However this just describes the relationship between planes in a metaphysical sense, how they conceptually align. I don't like models that attempt to pin down the planes in an actual topographical manner