It would be really interesting to see implemented the possibility to import gltf 1.0 and 2.0 file format. gltf is looking very good and a really open and optimized alternative to Autodesk fbx.
4.19 contains an experimental importer: https://forums.unrealengine.com/development-discussion/content-creation/1415582-the-new-gltf-import-supported-in-4-19-preview-is-awesome-experimentation
and they “hope to do some bigger enhancements for 4.20 and beyond”