Hello Andrew,
thank you for reporting. We are aware of current limitations of glTF importer and are doing some improvements for UE5. I will share your remark to the team, to see if it is something we could support.
Did you import through the Datasmith button? I tried on one of my sample with hierarchy and I got the nodes in the world outliner. Could you share the model and/or some screenshots?
Bests,
Flavien