Bone/skeleton/animation creation facilities, not just editing.
first off let me say that my experience with eu4 is limited, ive spent about 3 months on and off with udk3. If this facility does exist my apologies, it was certainly one feature i was hoping for.
Id like to see full skeleton creation and animation creation mechanics within UE4, allowing artists to simply pass up the static mesh if they want and importantly to allow editing of skeletons within the ue4 part of the pipeline. This would save on the reimports and also minimise the various technical issues many have when importing from opensource/affordable art packages, eg blender.