I have been able to successfully import assets using the commandlet, but I have been desperately trying to specify import settings while using the ImportAsets commandlet.
From https://github.com/EpicGames/UnrealEngine/blob/release/Engine/Source/Editor/UnrealEd/Private/Commandlets/ImportAssetsCommandlet.cpp
I understand that I should be creating a JSON file, but I cannot find what the expected contents of that file are.
Really all I want is to be able to specify that bCombineMeshes should be true, and bRemoveDegenerates should be true.