After godotengine/godot-proposals#5183, an argument can be made that the current name for SoftDynamicBody is also counterproductive to what the new Node naming scheme for Godot 4 aims to achieve. It's misleading, and the longer name doesn't add much meaning, but it typically gets a pass because it's not nearly as common as Rigid Bodies in game engines.

So "SoftDynamicBody" is not a physics body apparently, but I was misled thinking it was... Adds to the reasons I don't like the name. Really hoping a rename of RigidDynamicBody makes it into 4.0 so we don't just have to live with it

The name soft body has also been used to describe deformable objects in physics simulations longer than Godot has existed. I do not see a reason why this was changed.

SoftDynamicBody3D -> SoftBody3D
SoftDynamicBody3DGizmoPlugin -> SoftBody3DGizmoPlugin (this class is not exposed)

Affects the file names, as well.

Bugsquad edit: See also #64546 for RigidBody.