I did understood you before but what’s you are suggesting is none other then light baking just outside the engine with mariginal quality difference as of now (as materials will still be done in unreal engine) and as any kind of texture baking requires unwrapping, it’s only good if we remove this altogether, which is the underline problem cause here.
Lightmass is evolving and I also know that it’s still way far behind from some of the major offline render engines but as embree is already introduced and things are looking to turn around. I don’t believe only calcuting lighting with offline render engine will do the job here, there are so many things that need overhaul.
And I think there are different types of wheels for different needs.