Yaarel
🇮🇱 🇺🇦 He-Mage
The ethereal exists in 4e, in the sense that the "fey" and "shadow" are positive and negative aspects of it.The thing is, "ether" doesn't exist in the 4e cosmology. There is no Ethereal Plane in the World Axis. So, if you say to a sage in the Nentir Vale that there is some ethereal stuff doing "gravity" and whatnot, they are going to look at you and think you're nuts.
Even the shallow ethereal exists in the sense of "force" effects like Wall of Force and Magic Missile, which utilize "magical force", which serves as an other term for ether.
Also, while the "insubstantial" condition can apply variously, it includes the sense of becoming ethereal and ghostlike. This 4e insubstantiality corresponds to entering the shallow ethereal in other editions.
I see the shallow ether as the ethereal objects that are actually inside the material plane, including magical force and natural force like gravity. 4e tends to refer to the material plane as nature, the natural world, or the mortal world in the wider sense.
I prefer the way that 5e pulls everything together into a fifth elemental plane called the ethereal plane. But it is worth clarifying that the shallow ether is the aspect of ether that is actually inside and part of the material plane. I also like the way that 4e spells like Wall of Force and Magic Missile have the "force" tag that explicitly connects them to each other. 5e might use spell tags too like "ether" as a tag for effects like Magic Missile, Wall of Force, Fly, Telekinesis, Unseen Servant, Etherealness, and so on.