Empty nodes can still contain relevant information, so an option to export empty xforms for glTF would be preferred. There’s already an option to turn export on/off for visible objects but it doesn’t affect the outcome of xforms.
Additionally, it looks like the glTF exporter tries to be smart and merges xforms and their children together in pretty unpredicable ways; e.g. a : Xform > b : Mesh
ends up as a : Mesh
in the glTF file. Expected would be that the hierarchy stays as designed.