Deledrius wrote: I suspect that normal maps computed by the renderer will probably always be superior to ones converted from a flat texture.
I doubt it,
to my opinion the result of the renderer depends on the normals and not the other way around .
So you have to create the normals first before you can render it.
I am learning to handle the " unreal engine 4 " since a short period.
So i repeat all the lessons as teached by Epic in the many video 's which are available on youtube.
Have a look at this tutorial called " Introduction to Materials in UE4 - 3 - Adding Textures to a Material" :
Its a great example of how the bump is created from a texture to let the renderer behave as intended.